Basic DragImage implementation....

chrome/browser/gtk/tab_contents_drag_source.h

 // 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 CHROME_BROWSER_GTK_TAB_CONTENTS_DRAG_SOURCE_H_
 #define CHROME_BROWSER_GTK_TAB_CONTENTS_DRAG_SOURCE_H_
 
 #include <gtk/gtk.h>
 
 #include "app/gfx/native_widget_types.h"
 #include "base/basictypes.h"
 #include "base/file_path.h"
+#include "base/gfx/point.h"
 #include "base/message_loop.h"
 #include "base/string16.h"
 #include "googleurl/src/gurl.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebDragOperation.h"
 
 class TabContents;
 class TabContentsView;
 struct WebDropData;
 
 // TabContentsDragSource takes care of managing the drag from a TabContents
 // with Gtk.
 class TabContentsDragSource : public MessageLoopForUI::Observer {
  public:
   explicit TabContentsDragSource(TabContentsView* tab_contents_view);
   ~TabContentsDragSource();
 
   TabContents* tab_contents() const;
 
   // Starts a drag for the tab contents this TabContentsDragSource was
   // created for.
   void StartDragging(const WebDropData& drop_data,
-                     GdkEventButton* last_mouse_down);
+                     GdkEventButton* last_mouse_down,
+                     const SkBitmap& image,
+                     const gfx::Point& image_offset);
 
   // MessageLoop::Observer implementation:
   virtual void WillProcessEvent(GdkEvent* event);
   virtual void DidProcessEvent(GdkEvent* event);
 
  private:
   static gboolean OnDragFailedThunk(GtkWidget* widget,
                                     GdkDragContext* drag_context,
                                     GtkDragResult result,
                                     TabContentsDragSource* handler) {
@@ skipping 27 matching lines @@
 
   gfx::NativeView GetContentNativeView() const;
 
   // The view we're manging the drag for.
   TabContentsView* tab_contents_view_;
 
   // The drop data for the current drag (for drags that originate in the render
   // view). Non-NULL iff there is a current drag.
   scoped_ptr<WebDropData> drop_data_;
 
+  // The image used for depicting the drag, and the offset between the cursor
+  // and the top left pixel.
+  SkBitmap drag_image_;
+  gfx::Point image_offset_;
+
   // The mime type for the file contents of the current drag (if any).
   GdkAtom drag_file_mime_type_;
 
   // Whether the current drag has failed. Meaningless if we are not the source
   // for a current drag.
   bool drag_failed_;
 
   // This is the widget we use to initiate drags. Since we don't use the
   // renderer widget, we can persist drags even when our contents is switched
   // out.
   GtkWidget* drag_widget_;
 
   // The file mime type for a drag-out download.
   string16 wide_download_mime_type_;
 
   // The file name to be saved to for a drag-out download.
   FilePath download_file_name_;
 
   // The URL to download from for a drag-out download.
   GURL download_url_;
 
   DISALLOW_COPY_AND_ASSIGN(TabContentsDragSource);
 };
 
 #endif  // CHROME_BROWSER_GTK_TAB_CONTENTS_DRAG_SOURCE_H_