Add support for draggable regions (issue #1645).

Regions are defined using the '-webkit-app-region: drag/no-drag'
CSS property and passed to the CefDragHandler::
OnDraggableRegionsChanged callback.

cef.gyp

@@ -415,6 +415,7 @@
         'tests/unittests/display_unittest.cc',
         'tests/unittests/dom_unittest.cc',
         'tests/unittests/download_unittest.cc',
+        'tests/unittests/draggable_regions_unittest.cc',
         'tests/unittests/frame_unittest.cc',
         'tests/unittests/geolocation_unittest.cc',
         'tests/unittests/jsdialog_unittest.cc',

include/capi/cef_drag_handler_capi.h

@@ -66,6 +66,17 @@ typedef struct _cef_drag_handler_t {
   int (CEF_CALLBACK *on_drag_enter)(struct _cef_drag_handler_t* self,
       struct _cef_browser_t* browser, struct _cef_drag_data_t* dragData,
       cef_drag_operations_mask_t mask);
+
+  ///
+  // Called whenever draggable regions for the browser window change. These can
+  // be specified using the '-webkit-app-region: drag/no-drag' CSS-property. If
+  // draggable regions are never defined in a document this function will also
+  // never be called. If the last draggable region is removed from a document
+  // this function will be called with an NULL vector.
+  ///
+  void (CEF_CALLBACK *on_draggable_regions_changed)(
+      struct _cef_drag_handler_t* self, struct _cef_browser_t* browser,
+      size_t regionsCount, cef_draggable_region_t const* regions);
 } cef_drag_handler_t;
 
 

include/cef_drag_handler.h

@@ -61,6 +61,18 @@ class CefDragHandler : public virtual CefBase {
   virtual bool OnDragEnter(CefRefPtr<CefBrowser> browser,
                            CefRefPtr<CefDragData> dragData,
                            DragOperationsMask mask) { return false; }
+
+  ///
+  // Called whenever draggable regions for the browser window change. These can
+  // be specified using the '-webkit-app-region: drag/no-drag' CSS-property. If
+  // draggable regions are never defined in a document this method will also
+  // never be called. If the last draggable region is removed from a document
+  // this method will be called with an empty vector.
+  ///
+  /*--cef()--*/
+  virtual void OnDraggableRegionsChanged(
+      CefRefPtr<CefBrowser> browser,
+      const std::vector<CefDraggableRegion>& regions) {}
 };
 
 #endif  // CEF_INCLUDE_CEF_DRAG_HANDLER_H_

include/internal/cef_types.h

@@ -1265,6 +1265,21 @@ typedef struct _cef_size_t {
   int height;
 } cef_size_t;
 
+///
+// Structure representing a draggable region.
+///
+typedef struct _cef_draggable_region_t {
+  ///
+  // Bounds of the region.
+  ///
+  cef_rect_t bounds;
+
+  ///
+  // True (1) this this region is draggable and false (0) otherwise.
+  ///
+  int draggable;
+} cef_draggable_region_t;
+
 ///
 // Existing process IDs.
 ///

include/internal/cef_types_wrappers.h

@@ -257,6 +257,50 @@ inline bool operator!=(const CefSize& a, const CefSize& b) {
 }
 
 
+struct CefDraggableRegionTraits {
+  typedef cef_draggable_region_t struct_type;
+
+  static inline void init(struct_type* s) {}
+  static inline void clear(struct_type* s) {}
+
+  static inline void set(const struct_type* src, struct_type* target,
+      bool copy) {
+    *target = *src;
+  }
+};
+
+///
+// Class representing a draggable region.
+///
+class CefDraggableRegion : public CefStructBase<CefDraggableRegionTraits> {
+ public:
+  typedef CefStructBase<CefDraggableRegionTraits> parent;
+
+  CefDraggableRegion() : parent() {}
+  CefDraggableRegion(const cef_draggable_region_t& r)  // NOLINT(runtime/explicit)
+    : parent(r) {}
+  CefDraggableRegion(const CefDraggableRegion& r)  // NOLINT(runtime/explicit)
+    : parent(r) {}
+  CefDraggableRegion(const CefRect& bounds, bool draggable) : parent() {
+    Set(bounds, draggable);
+  }
+
+  void Set(const CefRect& bounds, bool draggable) {
+    this->bounds = bounds, this->draggable = draggable;
+  }
+};
+
+inline bool operator==(const CefDraggableRegion& a,
+    const CefDraggableRegion& b) {
+  return a.bounds == b.bounds && a.draggable == b.draggable;
+}
+
+inline bool operator!=(const CefDraggableRegion& a,
+    const CefDraggableRegion& b) {
+  return !(a == b);
+}
+
+
 struct CefScreenInfoTraits {
   typedef cef_screen_info_t struct_type;
 

libcef/browser/browser_host_impl.cc

@@ -2659,6 +2659,8 @@ bool CefBrowserHostImpl::OnMessageReceived(const IPC::Message& message) {
   IPC_BEGIN_MESSAGE_MAP(CefBrowserHostImpl, message)
     IPC_MESSAGE_HANDLER(CefHostMsg_FrameIdentified, OnFrameIdentified)
     IPC_MESSAGE_HANDLER(CefHostMsg_DidFinishLoad, OnDidFinishLoad)
+    IPC_MESSAGE_HANDLER(CefHostMsg_UpdateDraggableRegions,
+                        OnUpdateDraggableRegions)
     IPC_MESSAGE_HANDLER(CefHostMsg_Request, OnRequest)
     IPC_MESSAGE_HANDLER(CefHostMsg_Response, OnResponse)
     IPC_MESSAGE_HANDLER(CefHostMsg_ResponseAck, OnResponseAck)
@@ -2716,6 +2718,26 @@ void CefBrowserHostImpl::OnDidFinishLoad(int64 frame_id,
   OnLoadEnd(frame, validated_url, http_status_code);
 }
 
+void CefBrowserHostImpl::OnUpdateDraggableRegions(
+    const std::vector<Cef_DraggableRegion_Params>& regions) {
+  std::vector<CefDraggableRegion> draggable_regions;
+  draggable_regions.reserve(regions.size());
+
+  std::vector<Cef_DraggableRegion_Params>::const_iterator it = regions.begin();
+  for (; it != regions.end(); ++it) {
+    const gfx::Rect& rect(it->bounds);
+    const CefRect bounds(rect.x(), rect.y(), rect.width(), rect.height());
+    draggable_regions.push_back(CefDraggableRegion(bounds, it->draggable));
+  }
+
+  if (client_.get()) {
+    CefRefPtr<CefDragHandler> handler = client_->GetDragHandler();
+    if (handler.get()) {
+      handler->OnDraggableRegionsChanged(this, draggable_regions);
+    }
+  }
+}
+
 void CefBrowserHostImpl::OnRequest(const Cef_Request_Params& params) {
   bool success = false;
   std::string response;

libcef/browser/browser_host_impl.h

@@ -64,6 +64,7 @@ class Widget;
 class CefWindowX11;
 #endif
 
+struct Cef_DraggableRegion_Params;
 struct Cef_Request_Params;
 struct Cef_Response_Params;
 class CefBrowserInfo;
@@ -477,6 +478,8 @@ class CefBrowserHostImpl : public CefBrowserHost,
       const GURL& validated_url,
       bool is_main_frame,
       int http_status_code);
+  void OnUpdateDraggableRegions(
+      const std::vector<Cef_DraggableRegion_Params>& regions);
   void OnRequest(const Cef_Request_Params& params);
   void OnResponse(const Cef_Response_Params& params);
   void OnResponseAck(int request_id);

libcef/common/cef_messages.h

@@ -68,6 +68,12 @@ IPC_STRUCT_BEGIN(Cef_CrossOriginWhiteListEntry_Params)
   IPC_STRUCT_MEMBER(bool, allow_target_subdomains)
 IPC_STRUCT_END()
 
+// Parameters structure for a draggable region.
+IPC_STRUCT_BEGIN(Cef_DraggableRegion_Params)
+  IPC_STRUCT_MEMBER(gfx::Rect, bounds)
+  IPC_STRUCT_MEMBER(bool, draggable)
+IPC_STRUCT_END()
+
 
 // Messages sent from the browser to the renderer.
 
@@ -189,6 +195,10 @@ IPC_MESSAGE_ROUTED1(CefHostMsg_Response,
 IPC_MESSAGE_ROUTED1(CefHostMsg_ResponseAck,
                     int /* request_id */)
 
+// Sent by the renderer when the draggable regions are updated.
+IPC_MESSAGE_ROUTED1(CefHostMsg_UpdateDraggableRegions,
+                    std::vector<Cef_DraggableRegion_Params> /* regions */)
+
 
 // Singly-included section for struct and custom IPC traits.
 #ifndef CEF_LIBCEF_COMMON_CEF_MESSAGES_H_

libcef/renderer/browser_impl.cc

@@ -571,6 +571,19 @@ void CefBrowserImpl::FocusedNodeChanged(const blink::WebNode& node) {
   }
 }
 
+void CefBrowserImpl::DraggableRegionsChanged(blink::WebFrame* frame) {
+  blink::WebVector<blink::WebDraggableRegion> webregions =
+      frame->document().draggableRegions();
+  std::vector<Cef_DraggableRegion_Params> regions;
+  for (size_t i = 0; i < webregions.size(); ++i) {
+    Cef_DraggableRegion_Params region;
+    region.bounds = webregions[i].bounds;
+    region.draggable = webregions[i].draggable;
+    regions.push_back(region);
+  }
+  Send(new CefHostMsg_UpdateDraggableRegions(routing_id(), regions));
+}
+
 bool CefBrowserImpl::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(CefBrowserImpl, message)

libcef/renderer/browser_impl.h

@@ -119,6 +119,7 @@ class CefBrowserImpl : public CefBrowser,
                                 bool is_new_navigation) override;
   void FrameDetached(blink::WebFrame* frame) override;
   void FocusedNodeChanged(const blink::WebNode& node) override;
+  void DraggableRegionsChanged(blink::WebFrame* frame) override;
   bool OnMessageReceived(const IPC::Message& message) override;
 
   // RenderViewObserver::OnMessageReceived message handlers.

libcef_dll/cpptoc/drag_handler_cpptoc.cc

@@ -46,6 +46,37 @@ int CEF_CALLBACK drag_handler_on_drag_enter(struct _cef_drag_handler_t* self,
   return _retval;
 }
 
+void CEF_CALLBACK drag_handler_on_draggable_regions_changed(
+    struct _cef_drag_handler_t* self, cef_browser_t* browser,
+    size_t regionsCount, cef_draggable_region_t const* regions) {
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  DCHECK(self);
+  if (!self)
+    return;
+  // Verify param: browser; type: refptr_diff
+  DCHECK(browser);
+  if (!browser)
+    return;
+  // Verify param: regions; type: simple_vec_byref_const
+  DCHECK(regionsCount == 0 || regions);
+  if (regionsCount > 0 && !regions)
+    return;
+
+  // Translate param: regions; type: simple_vec_byref_const
+  std::vector<CefDraggableRegion > regionsList;
+  if (regionsCount > 0) {
+    for (size_t i = 0; i < regionsCount; ++i) {
+      regionsList.push_back(regions[i]);
+    }
+  }
+
+  // Execute
+  CefDragHandlerCppToC::Get(self)->OnDraggableRegionsChanged(
+      CefBrowserCToCpp::Wrap(browser),
+      regionsList);
+}
+
 }  // namespace
 
 
@@ -53,6 +84,8 @@ int CEF_CALLBACK drag_handler_on_drag_enter(struct _cef_drag_handler_t* self,
 
 CefDragHandlerCppToC::CefDragHandlerCppToC() {
   GetStruct()->on_drag_enter = drag_handler_on_drag_enter;
+  GetStruct()->on_draggable_regions_changed =
+      drag_handler_on_draggable_regions_changed;
 }
 
 template<> CefRefPtr<CefDragHandler> CefCppToC<CefDragHandlerCppToC,

libcef_dll/ctocpp/drag_handler_ctocpp.cc

@@ -44,6 +44,44 @@ bool CefDragHandlerCToCpp::OnDragEnter(CefRefPtr<CefBrowser> browser,
   return _retval?true:false;
 }
 
+void CefDragHandlerCToCpp::OnDraggableRegionsChanged(
+    CefRefPtr<CefBrowser> browser,
+    const std::vector<CefDraggableRegion>& regions) {
+  cef_drag_handler_t* _struct = GetStruct();
+  if (CEF_MEMBER_MISSING(_struct, on_draggable_regions_changed))
+    return;
+
+  // AUTO-GENERATED CONTENT - DELETE THIS COMMENT BEFORE MODIFYING
+
+  // Verify param: browser; type: refptr_diff
+  DCHECK(browser.get());
+  if (!browser.get())
+    return;
+
+  // Translate param: regions; type: simple_vec_byref_const
+  const size_t regionsCount = regions.size();
+  cef_draggable_region_t* regionsList = NULL;
+  if (regionsCount > 0) {
+    regionsList = new cef_draggable_region_t[regionsCount];
+    DCHECK(regionsList);
+    if (regionsList) {
+      for (size_t i = 0; i < regionsCount; ++i) {
+        regionsList[i] = regions[i];
+      }
+    }
+  }
+
+  // Execute
+  _struct->on_draggable_regions_changed(_struct,
+      CefBrowserCppToC::Wrap(browser),
+      regionsCount,
+      regionsList);
+
+  // Restore param:regions; type: simple_vec_byref_const
+  if (regionsList)
+    delete [] regionsList;
+}
+
 
 // CONSTRUCTOR - Do not edit by hand.
 

libcef_dll/ctocpp/drag_handler_ctocpp.h

@@ -18,6 +18,7 @@
 #pragma message("Warning: "__FILE__" may be accessed DLL-side only")
 #else  // BUILDING_CEF_SHARED
 
+#include <vector>
 #include "include/cef_drag_handler.h"
 #include "include/capi/cef_drag_handler_capi.h"
 #include "libcef_dll/ctocpp/ctocpp.h"
@@ -33,6 +34,8 @@ class CefDragHandlerCToCpp
   // CefDragHandler methods.
   bool OnDragEnter(CefRefPtr<CefBrowser> browser,
       CefRefPtr<CefDragData> dragData, DragOperationsMask mask) override;
+  void OnDraggableRegionsChanged(CefRefPtr<CefBrowser> browser,
+      const std::vector<CefDraggableRegion>& regions) override;
 };
 
 #endif  // BUILDING_CEF_SHARED

tests/cefclient/browser/browser_window.cc

@@ -68,4 +68,10 @@ void BrowserWindow::OnSetLoadingState(bool isLoading,
   delegate_->OnSetLoadingState(isLoading, canGoBack, canGoForward);
 }
 
+void BrowserWindow::OnSetDraggableRegions(
+      const std::vector<CefDraggableRegion>& regions) {
+  REQUIRE_MAIN_THREAD();
+  delegate_->OnSetDraggableRegions(regions);
+}
+
 }  // namespace client

tests/cefclient/browser/browser_window.h

@@ -39,6 +39,10 @@ class BrowserWindow : public ClientHandler::Delegate {
                                    bool canGoBack,
                                    bool canGoForward) = 0;
 
+    // Set the draggable regions.
+    virtual void OnSetDraggableRegions(
+        const std::vector<CefDraggableRegion>& regions) = 0;
+
    protected:
     virtual ~Delegate() {}
   };
@@ -101,6 +105,8 @@ class BrowserWindow : public ClientHandler::Delegate {
   void OnSetLoadingState(bool isLoading,
                          bool canGoBack,
                          bool canGoForward) OVERRIDE;
+  void OnSetDraggableRegions(
+      const std::vector<CefDraggableRegion>& regions) OVERRIDE;
 
   Delegate* delegate_;
   CefRefPtr<CefBrowser> browser_;

tests/cefclient/browser/client_handler.cc

@@ -290,6 +290,14 @@ bool ClientHandler::OnDragEnter(CefRefPtr<CefBrowser> browser,
   return false;
 }
 
+void ClientHandler::OnDraggableRegionsChanged(
+    CefRefPtr<CefBrowser> browser,
+    const std::vector<CefDraggableRegion>& regions) {
+  CEF_REQUIRE_UI_THREAD();
+
+  NotifyDraggableRegions(regions);
+}
+
 bool ClientHandler::OnRequestGeolocationPermission(
       CefRefPtr<CefBrowser> browser,
       const CefString& requesting_url,
@@ -676,6 +684,19 @@ void ClientHandler::NotifyLoadingState(bool isLoading,
     delegate_->OnSetLoadingState(isLoading, canGoBack, canGoForward);
 }
 
+void ClientHandler::NotifyDraggableRegions(
+    const std::vector<CefDraggableRegion>& regions) {
+  if (!CURRENTLY_ON_MAIN_THREAD()) {
+    // Execute this method on the main thread.
+    MAIN_POST_CLOSURE(
+        base::Bind(&ClientHandler::NotifyDraggableRegions, this, regions));
+    return;
+  }
+
+  if (delegate_)
+    delegate_->OnSetDraggableRegions(regions);
+}
+
 void ClientHandler::BuildTestMenu(CefRefPtr<CefMenuModel> model) {
   if (model->GetCount() > 0)
     model->AddSeparator();

tests/cefclient/browser/client_handler.h

@@ -57,6 +57,10 @@ class ClientHandler : public CefClient,
                                    bool canGoBack,
                                    bool canGoForward) = 0;
 
+    // Set the draggable regions.
+    virtual void OnSetDraggableRegions(
+        const std::vector<CefDraggableRegion>& regions) = 0;
+
    protected:
     virtual ~Delegate() {}
   };
@@ -152,6 +156,10 @@ class ClientHandler : public CefClient,
                    CefRefPtr<CefDragData> dragData,
                    CefDragHandler::DragOperationsMask mask) OVERRIDE;
 
+  void OnDraggableRegionsChanged(
+      CefRefPtr<CefBrowser> browser,
+      const std::vector<CefDraggableRegion>& regions) OVERRIDE;
+
   // CefGeolocationHandler methods
   bool OnRequestGeolocationPermission(
       CefRefPtr<CefBrowser> browser,
@@ -263,6 +271,8 @@ class ClientHandler : public CefClient,
   void NotifyLoadingState(bool isLoading,
                           bool canGoBack,
                           bool canGoForward);
+  void NotifyDraggableRegions(
+      const std::vector<CefDraggableRegion>& regions);
 
   // Test context menu creation.
   void BuildTestMenu(CefRefPtr<CefMenuModel> model);
@@ -288,7 +298,7 @@ class ClientHandler : public CefClient,
   // Handles the browser side of query routing. The renderer side is handled
   // in client_renderer.cc.
   CefRefPtr<CefMessageRouterBrowserSide> message_router_;
-  
+
   // MAIN THREAD MEMBERS
   // The following members will only be accessed on the main thread. This will
   // be the same as the CEF UI thread except when using multi-threaded message

tests/cefclient/browser/root_window_gtk.cc

@@ -387,6 +387,12 @@ void RootWindowGtk::OnSetLoadingState(bool isLoading,
   }
 }
 
+void RootWindowGtk::OnSetDraggableRegions(
+    const std::vector<CefDraggableRegion>& regions) {
+  REQUIRE_MAIN_THREAD();
+  // TODO(cef): Implement support for draggable regions on this platform.
+}
+
 void RootWindowGtk::NotifyDestroyedIfDone() {
   // Notify once both the window and the browser have been destroyed.
   if (window_destroyed_ && browser_destroyed_)

tests/cefclient/browser/root_window_gtk.h

@@ -58,6 +58,8 @@ class RootWindowGtk : public RootWindow,
   void OnSetLoadingState(bool isLoading,
                          bool canGoBack,
                          bool canGoForward) OVERRIDE;
+  void OnSetDraggableRegions(
+      const std::vector<CefDraggableRegion>& regions) OVERRIDE;
 
   void NotifyDestroyedIfDone();
 

tests/cefclient/browser/root_window_mac.h

@@ -64,6 +64,8 @@ class RootWindowMac : public RootWindow,
   void OnSetLoadingState(bool isLoading,
                          bool canGoBack,
                          bool canGoForward) OVERRIDE;
+  void OnSetDraggableRegions(
+      const std::vector<CefDraggableRegion>& regions) OVERRIDE;
 
   void NotifyDestroyedIfDone();
 

tests/cefclient/browser/root_window_mac.mm

@@ -576,6 +576,12 @@ void RootWindowMac::OnSetAddress(const std::string& url) {
   }
 }
 
+void RootWindowMac::OnSetDraggableRegions(
+    const std::vector<CefDraggableRegion>& regions) {
+  REQUIRE_MAIN_THREAD();
+  // TODO(cef): Implement support for draggable regions on this platform.
+}
+
 void RootWindowMac::OnSetTitle(const std::string& title) {
   REQUIRE_MAIN_THREAD();
 

tests/cefclient/browser/root_window_win.cc

@@ -5,6 +5,7 @@
 #include "cefclient/browser/root_window_win.h"
 
 #include "include/base/cef_bind.h"
+#include "include/base/cef_build.h"
 #include "include/cef_app.h"
 #include "cefclient/browser/browser_window_osr_win.h"
 #include "cefclient/browser/browser_window_std_win.h"
@@ -51,6 +52,7 @@ RootWindowWin::RootWindowWin()
       start_rect_(),
       initialized_(false),
       hwnd_(NULL),
+      draggable_region_(NULL),
       back_hwnd_(NULL),
       forward_hwnd_(NULL),
       reload_hwnd_(NULL),
@@ -66,11 +68,16 @@ RootWindowWin::RootWindowWin()
       window_destroyed_(false),
       browser_destroyed_(false) {
   find_buff_[0] = 0;
+
+  // Create a HRGN representing the draggable window area.
+  draggable_region_ = ::CreateRectRgn(0, 0, 0, 0);
 }
 
 RootWindowWin::~RootWindowWin() {
   REQUIRE_MAIN_THREAD();
 
+  ::DeleteObject(draggable_region_);
+
   // The window and browser should already have been destroyed.
   DCHECK(window_destroyed_);
   DCHECK(browser_destroyed_);
@@ -513,6 +520,21 @@ LRESULT CALLBACK RootWindowWin::RootWndProc(HWND hWnd, UINT message,
         return 0;  // Cancel the close.
       break;
 
+    case WM_NCHITTEST: {
+      LRESULT hit = DefWindowProc(hWnd, message, wParam, lParam);
+      if (hit == HTCLIENT) {
+        POINTS points = MAKEPOINTS(lParam);
+        POINT point = { points.x, points.y };
+        ::ScreenToClient(hWnd, &point);
+        if (::PtInRegion(self->draggable_region_, point.x, point.y)) {
+          // If cursor is inside a draggable region return HTCAPTION to allow
+          // dragging.
+          return HTCAPTION;
+        }
+      }
+      return hit;
+    }
+
     case WM_NCDESTROY:
       // Clear the reference to |self|.
       SetUserDataPtr(hWnd, NULL);
@@ -764,6 +786,111 @@ void RootWindowWin::OnSetLoadingState(bool isLoading,
   }
 }
 
+namespace {
+
+LPCWSTR kParentWndProc = L"CefParentWndProc";
+LPCWSTR kDraggableRegion = L"CefDraggableRegion";
+
+LRESULT CALLBACK SubclassedWindowProc(
+    HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
+  WNDPROC hParentWndProc = reinterpret_cast<WNDPROC>(
+      ::GetPropW(hWnd, kParentWndProc));
+  HRGN hRegion = reinterpret_cast<HRGN>(
+      ::GetPropW(hWnd, kDraggableRegion));
+
+  if (message == WM_NCHITTEST) {
+    LRESULT hit = CallWindowProc(
+        hParentWndProc, hWnd, message, wParam, lParam);
+    if (hit == HTCLIENT) {
+      POINTS points = MAKEPOINTS(lParam);
+      POINT point = { points.x, points.y };
+      ::ScreenToClient(hWnd, &point);
+      if (::PtInRegion(hRegion, point.x, point.y)) {
+        // Let the parent window handle WM_NCHITTEST by returning HTTRANSPARENT
+        // in child windows.
+        return HTTRANSPARENT;
+      }
+    }
+    return hit;
+  }
+
+  return CallWindowProc(hParentWndProc, hWnd, message, wParam, lParam);
+}
+
+void SubclassWindow(HWND hWnd, HRGN hRegion) {
+  HANDLE hParentWndProc = ::GetPropW(hWnd, kParentWndProc);
+  if (hParentWndProc) {
+    return;
+  }
+
+  SetLastError(0);
+  LONG_PTR hOldWndProc = SetWindowLongPtr(
+      hWnd, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(SubclassedWindowProc));
+  if (hOldWndProc == 0 && GetLastError() != ERROR_SUCCESS) {
+    return;
+  }
+
+  ::SetPropW(hWnd, kParentWndProc, reinterpret_cast<HANDLE>(hOldWndProc));
+  ::SetPropW(hWnd, kDraggableRegion, reinterpret_cast<HANDLE>(hRegion));
+}
+
+void UnSubclassWindow(HWND hWnd) {
+  LONG_PTR hParentWndProc = reinterpret_cast<LONG_PTR>(
+    ::GetPropW(hWnd, kParentWndProc));
+  if (hParentWndProc) {
+      LONG_PTR hPreviousWndProc =
+          SetWindowLongPtr(hWnd, GWLP_WNDPROC, hParentWndProc);
+      ALLOW_UNUSED_LOCAL(hPreviousWndProc);
+      DCHECK_EQ(hPreviousWndProc,
+                reinterpret_cast<LONG_PTR>(SubclassedWindowProc));
+  }
+
+  ::RemovePropW(hWnd, kParentWndProc);
+  ::RemovePropW(hWnd, kDraggableRegion);
+}
+
+BOOL CALLBACK SubclassWindowsProc(HWND hwnd, LPARAM lParam) {
+  SubclassWindow(hwnd, reinterpret_cast<HRGN>(lParam));
+  return TRUE;
+}
+
+BOOL CALLBACK UnSubclassWindowsProc(HWND hwnd, LPARAM lParam) {
+  UnSubclassWindow(hwnd);
+  return TRUE;
+}
+
+}  // namespace
+
+void RootWindowWin::OnSetDraggableRegions(
+    const std::vector<CefDraggableRegion>& regions) {
+  REQUIRE_MAIN_THREAD();
+
+  // Reset draggable region.
+  ::SetRectRgn(draggable_region_, 0, 0, 0, 0);
+
+  // Determine new draggable region.
+  std::vector<CefDraggableRegion>::const_iterator it = regions.begin();
+  for (;it != regions.end(); ++it) {
+    HRGN region = ::CreateRectRgn(
+        it->bounds.x, it->bounds.y,
+        it->bounds.x + it->bounds.width,
+        it->bounds.y + it->bounds.height);
+    ::CombineRgn(
+        draggable_region_, draggable_region_, region,
+        it->draggable ? RGN_OR : RGN_DIFF);
+    ::DeleteObject(region);
+  }
+
+  // Subclass child window procedures in order to do hit-testing.
+  // This will be a no-op, if it is already subclassed.
+  if (hwnd_) {
+    WNDENUMPROC proc = !regions.empty() ?
+        SubclassWindowsProc : UnSubclassWindowsProc;
+    ::EnumChildWindows(
+        hwnd_, proc, reinterpret_cast<LPARAM>(draggable_region_));
+  }
+}
+
 void RootWindowWin::NotifyDestroyedIfDone() {
   // Notify once both the window and the browser have been destroyed.
   if (window_destroyed_ && browser_destroyed_)

tests/cefclient/browser/root_window_win.h

@@ -90,6 +90,8 @@ class RootWindowWin : public RootWindow,
   void OnSetLoadingState(bool isLoading,
                          bool canGoBack,
                          bool canGoForward) OVERRIDE;
+  void OnSetDraggableRegions(
+      const std::vector<CefDraggableRegion>& regions) OVERRIDE;
 
   void NotifyDestroyedIfDone();
 
@@ -106,6 +108,9 @@ class RootWindowWin : public RootWindow,
   // Main window.
   HWND hwnd_;
 
+  // Draggable region.
+  HRGN draggable_region_;
+
   // Buttons.
   HWND back_hwnd_;
   HWND forward_hwnd_;
@@ -115,7 +120,7 @@ class RootWindowWin : public RootWindow,
   // URL text field.
   HWND edit_hwnd_;
   WNDPROC edit_wndproc_old_;
-  
+
   // Find dialog.
   HWND find_hwnd_;
   UINT find_message_id_;

tests/unittests/draggable_regions_unittest.cc

@@ -0,0 +1,171 @@
+// Copyright (c) 2015 The Chromium Embedded Framework Authors. All rights
+// reserved. Use of this source code is governed by a BSD-style license that
+// can be found in the LICENSE file.
+
+// Include this first to avoid type conflicts with CEF headers.
+#include "tests/unittests/chromium_includes.h"
+
+#include "include/wrapper/cef_closure_task.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "tests/unittests/test_handler.h"
+
+namespace {
+
+const char kTestURLWithRegions[] = "http://test.com/regions";
+const char kTestHTMLWithRegions[] =
+    "<html>"
+    "  <body>"
+    "    <div style=\"position: absolute; top: 50px; left: 50px; width: 200px; "
+    "height: 200px; background-color: red; -webkit-app-region: drag;\">"
+    "      <div style=\"position: absolute; top: 50%; left: 50%; "
+    "transform: translate(-50%, -50%); width: 50px; height: 50px; "
+    "background-color: blue; -webkit-app-region: no-drag;\">"
+    "      </div>"
+    "    </div>"
+    "  </body>"
+    "</html>";
+
+const char kTestURLWithoutRegions[] = "http://test.com/no-regions";
+const char kTestHTMLWithoutRegions[] =
+    "<html><body>Hello World!</body></html>";
+
+const char kTestURLWithChangingRegions[] = "http://test.com/changing-regions";
+const char kTestHTMLWithChangingRegions[] =
+    "<html>"
+    "  <body>"
+    "    <div id=\"layer\" style=\"position: absolute; top: 50px; left: 50px; "
+    "width: 200px; height: 200px; background-color: red; "
+    "-webkit-app-region: drag;\">"
+    "      <div style=\"position: absolute; top: 50%; left: 50%; "
+    "transform: translate(-50%, -50%); width: 50px; height: 50px; "
+    "background-color: blue; -webkit-app-region: no-drag;\">"
+    "      </div>"
+    "    </div>"
+    "    <script>"
+    "      window.setTimeout(function() {"
+    "        var layer = document.getElementById('layer');"
+    "        layer.style.top = '0px';"
+    "        layer.style.left = '0px';"
+    "      }, 500);"
+    "    </script>"
+    "  </body>"
+    "</html>";
+
+class DraggableRegionsTestHandler : public TestHandler {
+ public:
+  DraggableRegionsTestHandler()
+    : step_(kStepWithRegions) {}
+
+  void RunTest() override {
+    // Add HTML documents with and without draggable regions.
+    AddResource(kTestURLWithRegions, kTestHTMLWithRegions, "text/html");
+    AddResource(kTestURLWithoutRegions, kTestHTMLWithoutRegions, "text/html");
+    AddResource(kTestURLWithChangingRegions, kTestHTMLWithChangingRegions,
+                "text/html");
+
+    // Create the browser
+    CreateBrowser(kTestURLWithRegions);
+
+    // Time out the test after a reasonable period of time.
+    SetTestTimeout();
+  }
+
+  void OnDraggableRegionsChanged(
+      CefRefPtr<CefBrowser> browser,
+      const std::vector<CefDraggableRegion>& regions) override {
+    EXPECT_TRUE(CefCurrentlyOn(TID_UI));
+    EXPECT_TRUE(browser->IsSame(GetBrowser()));
+
+    did_call_on_draggable_regions_changed_.yes();
+
+    switch (step_) {
+      case kStepWithRegions:
+      case kStepWithChangingRegions1:
+        EXPECT_EQ(2U, regions.size());
+        EXPECT_EQ(50, regions[0].bounds.x);
+        EXPECT_EQ(50, regions[0].bounds.y);
+        EXPECT_EQ(200, regions[0].bounds.width);
+        EXPECT_EQ(200, regions[0].bounds.height);
+        EXPECT_EQ(1, regions[0].draggable);
+        EXPECT_EQ(125, regions[1].bounds.x);
+        EXPECT_EQ(125, regions[1].bounds.y);
+        EXPECT_EQ(50, regions[1].bounds.width);
+        EXPECT_EQ(50, regions[1].bounds.height);
+        EXPECT_EQ(0, regions[1].draggable);
+        break;
+      case kStepWithChangingRegions2:
+        EXPECT_EQ(2U, regions.size());
+        EXPECT_EQ(0, regions[0].bounds.x);
+        EXPECT_EQ(0, regions[0].bounds.y);
+        EXPECT_EQ(200, regions[0].bounds.width);
+        EXPECT_EQ(200, regions[0].bounds.height);
+        EXPECT_EQ(1, regions[0].draggable);
+        EXPECT_EQ(75, regions[1].bounds.x);
+        EXPECT_EQ(75, regions[1].bounds.y);
+        EXPECT_EQ(50, regions[1].bounds.width);
+        EXPECT_EQ(50, regions[1].bounds.height);
+        EXPECT_EQ(0, regions[1].draggable);
+        break;
+      case kStepWithoutRegions:
+        // Should not be reached.
+        EXPECT_TRUE(false);
+        break;
+    }
+
+    NextTest(browser);
+  }
+
+  void DestroyTest() override {
+    EXPECT_EQ(false, did_call_on_draggable_regions_changed_);
+
+    TestHandler::DestroyTest();
+  }
+
+ private:
+  void NextTest(CefRefPtr<CefBrowser> browser) {
+    CefRefPtr<CefFrame> frame(browser->GetMainFrame());
+
+    did_call_on_draggable_regions_changed_.reset();
+
+    switch (step_) {
+      case kStepWithRegions:
+        step_ = kStepWithChangingRegions1;
+        frame->LoadURL(kTestURLWithChangingRegions);
+        break;
+      case kStepWithChangingRegions1:
+        step_ = kStepWithChangingRegions2;
+        break;
+      case kStepWithChangingRegions2:
+        step_ = kStepWithoutRegions;
+        frame->LoadURL(kTestURLWithoutRegions);
+        // Needed because this test doesn't call OnDraggableRegionsChanged.
+        CefPostDelayedTask(TID_UI,
+            base::Bind(&DraggableRegionsTestHandler::DestroyTest, this), 500);
+        break;
+      case kStepWithoutRegions: {
+        // Should not be reached.
+        EXPECT_TRUE(false);
+        break;
+      }
+    }
+  }
+
+  enum Step {
+    kStepWithRegions,
+    kStepWithChangingRegions1,
+    kStepWithChangingRegions2,
+    kStepWithoutRegions,
+  } step_;
+
+  TrackCallback did_call_on_draggable_regions_changed_;
+};
+
+}  // namespace
+
+// Verify that draggable regions work.
+TEST(DraggableRegionsTest, DraggableRegions) {
+  CefRefPtr<DraggableRegionsTestHandler> handler =
+      new DraggableRegionsTestHandler();
+  handler->ExecuteTest();
+  ReleaseAndWaitForDestructor(handler);
+}

tests/unittests/os_rendering_unittest.cc

@@ -805,7 +805,7 @@ class OSRTestHandler : public RoutingTestHandler,
 
   bool StartDragging(CefRefPtr<CefBrowser> browser,
                      CefRefPtr<CefDragData> drag_data,
-                     DragOperationsMask allowed_ops,
+                     CefRenderHandler::DragOperationsMask allowed_ops,
                      int x, int y) override {
     if (test_type_ == OSR_TEST_DRAG_DROP_START_DRAGGING && started()) {
       DestroySucceededTestSoon();

tests/unittests/test_handler.h

@@ -37,6 +37,7 @@ class TestHandler : public CefClient,
                     public CefDialogHandler,
                     public CefDisplayHandler,
                     public CefDownloadHandler,
+                    public CefDragHandler,
                     public CefGeolocationHandler,
                     public CefJSDialogHandler,
                     public CefLifeSpanHandler,
@@ -139,6 +140,9 @@ class TestHandler : public CefClient,
   CefRefPtr<CefDownloadHandler> GetDownloadHandler() override {
     return this;
   }
+  CefRefPtr<CefDragHandler> GetDragHandler() override {
+    return this;
+  }
   CefRefPtr<CefGeolocationHandler> GetGeolocationHandler() override {
     return this;
   }
@@ -162,6 +166,11 @@ class TestHandler : public CefClient,
       const CefString& suggested_name,
       CefRefPtr<CefBeforeDownloadCallback> callback) override {}
 
+  // CefDragHandler methods
+  void OnDraggableRegionsChanged(
+      CefRefPtr<CefBrowser> browser,
+      const std::vector<CefDraggableRegion>& regions) override {}
+
   // CefLifeSpanHandler methods
   void OnAfterCreated(CefRefPtr<CefBrowser> browser) override;
   void OnBeforeClose(CefRefPtr<CefBrowser> browser) override;

tools/cef_parser.py

@@ -403,6 +403,7 @@ _simpletypes = {
     'CefPoint' : ['cef_point_t', 'CefPoint()'],
     'CefRect' : ['cef_rect_t', 'CefRect()'],
     'CefSize' : ['cef_size_t', 'CefSize()'],
+    'CefDraggableRegion' : ['cef_draggable_region_t', 'CefDraggableRegion()'],
     'CefPageRange' : ['cef_page_range_t', 'CefPageRange()'],
     'CefThreadId' : ['cef_thread_id_t', 'TID_UI'],
     'CefTime' : ['cef_time_t', 'CefTime()'],