Add drag and drop support for Windows (issue #140).

git-svn-id: https://chromiumembedded.googlecode.com/svn/trunk@194 5089003a-bbd8-11dd-ad1f-f1f9622dbc98

libcef/browser_drag_delegate_win.h

@@ -0,0 +1,102 @@
+// Copyright (c) 2011 The Chromium Embedded Framework Authors.
+// Portions copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef _BROWSER_DRAG_DELEGATE_WIN_H
+#define _BROWSER_DRAG_DELEGATE_WIN_H
+#pragma once
+
+#include "base/ref_counted.h"
+#include "base/scoped_ptr.h"
+#include "base/threading/platform_thread.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebDragOperation.h"
+#include "ui/base/dragdrop/os_exchange_data_provider_win.h"
+#include "ui/gfx/point.h"
+
+class BrowserWebViewDelegate;
+class DragDropThread;
+class WebDragSource;
+struct WebDropData;
+
+// Windows-specific drag-and-drop handling.
+// If we are dragging a virtual file out of the browser, we use a background
+// thread to do the drag-and-drop because we do not want to run nested
+// message loop in the UI thread. For all other cases, the drag-and-drop happens
+// in the UI thread.
+class BrowserDragDelegate
+    : public ui::DataObjectImpl::Observer,
+      public base::RefCountedThreadSafe<BrowserDragDelegate> {
+ public:
+  explicit BrowserDragDelegate(BrowserWebViewDelegate* view);
+  virtual ~BrowserDragDelegate();
+
+  // Called on UI thread.
+  void StartDragging(const WebDropData& drop_data,
+                     WebKit::WebDragOperationsMask ops,
+                     const SkBitmap& image,
+                     const gfx::Point& image_offset);
+  void CancelDrag();
+
+  // DataObjectImpl::Observer implementation.
+  // Called on drag-and-drop thread.
+  virtual void OnWaitForData();
+  virtual void OnDataObjectDisposed();
+
+ private:
+  // Called on either UI thread or drag-and-drop thread.
+  void PrepareDragForDownload(const WebDropData& drop_data,
+                              ui::OSExchangeData* data,
+                              const GURL& page_url,
+                              const std::string& page_encoding);
+  void PrepareDragForFileContents(const WebDropData& drop_data,
+                                  ui::OSExchangeData* data);
+  void PrepareDragForUrl(const WebDropData& drop_data,
+                         ui::OSExchangeData* data);
+  void DoDragging(const WebDropData& drop_data,
+                  WebKit::WebDragOperationsMask ops,
+                  const GURL& page_url,
+                  const std::string& page_encoding,
+                  const SkBitmap& image,
+                  const gfx::Point& image_offset);
+
+  // Called on drag-and-drop thread.
+  void StartBackgroundDragging(const WebDropData& drop_data,
+                               WebKit::WebDragOperationsMask ops,
+                               const GURL& page_url,
+                               const std::string& page_encoding,
+                               const SkBitmap& image,
+                               const gfx::Point& image_offset);
+  // Called on UI thread.
+  void EndDragging(bool restore_suspended_state);
+  void CloseThread();
+
+  // For debug check only. Access only on drag-and-drop thread.
+  base::PlatformThreadId drag_drop_thread_id_;
+
+  // All the member variables below are accessed on UI thread.
+
+  // Keep track of the BrowserWebViewDelegate it is associated with.
+  BrowserWebViewDelegate* view_;
+
+  // |drag_source_| is our callback interface passed to the system when we
+  // want to initiate a drag and drop operation.  We use it to tell if a
+  // drag operation is happening.
+  scoped_refptr<WebDragSource> drag_source_;
+
+  // The thread used by the drag-out download. This is because we want to avoid
+  // running nested message loop in main UI thread.
+  scoped_ptr<DragDropThread> drag_drop_thread_;
+
+  // The flag to guard that EndDragging is not called twice.
+  bool drag_ended_;
+
+  // Keep track of the old suspended state of the drop target.
+  bool old_drop_target_suspended_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(BrowserDragDelegate);
+};
+
+
+#endif  // _BROWSER_DRAG_DELEGATE_WIN_H