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/web_drop_target_win.h

@@ -0,0 +1,68 @@
+// Copyright (c) 2011 The Chromium Embedded Framework Authors.
+// Portions copyright (c) 2010 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 _WEB_DROP_TARGET_WIN_H
+#define _WEB_DROP_TARGET_WIN_H
+#pragma once
+
+#include "base/scoped_ptr.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebDragOperation.h"
+#include "ui/base/dragdrop/drop_target.h"
+
+namespace WebKit {
+class WebView;
+};
+class WebViewHost;
+
+// A helper object that provides drop capabilities to a WebView. The
+// DropTarget handles drags that enter the region of the WebView by
+// passing on the events to the renderer.
+class WebDropTarget : public ui::DropTarget {
+ public:
+  // Create a new WebDropTarget associating it with the given HWND and
+  // WebView.
+  WebDropTarget(HWND source_hwnd, WebKit::WebView* view);
+  virtual ~WebDropTarget();
+
+  void set_drag_cursor(WebKit::WebDragOperation op) {
+    drag_cursor_ = op;
+  }
+
+ protected:
+  virtual DWORD OnDragEnter(IDataObject* data_object,
+                            DWORD key_state,
+                            POINT cursor_position,
+                            DWORD effect);
+
+  virtual DWORD OnDragOver(IDataObject* data_object,
+                           DWORD key_state,
+                           POINT cursor_position,
+                           DWORD effect);
+
+  virtual void OnDragLeave(IDataObject* data_object);
+
+  virtual DWORD OnDrop(IDataObject* data_object,
+                       DWORD key_state,
+                       POINT cursor_position,
+                       DWORD effect);
+
+ private:
+  // Our associated WebView.
+  WebKit::WebView* view_;
+
+  // We keep track of the web view host we're dragging over.  If it changes
+  // during a drag, we need to re-send the DragEnter message.  WARNING:
+  // this pointer should never be dereferenced.  We only use it for comparing
+  // pointers.
+  WebViewHost* current_wvh_;
+
+  // Used to determine what cursor we should display when dragging over web
+  // content area.  This can be updated async during a drag operation.
+  WebKit::WebDragOperation drag_cursor_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebDropTarget);
+};
+
+#endif  // _WEB_DROP_TARGET_WIN_H