Basic DragImage implementation....

chrome/browser/tab_contents/tab_contents_view_mac.mm

 // 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.
 
 #import <Carbon/Carbon.h>
 
 #include "chrome/browser/tab_contents/tab_contents_view_mac.h"
 
 #include <string>
 
@@ skipping 108 matching lines @@
 }
 
 gfx::NativeWindow TabContentsViewMac::GetTopLevelNativeWindow() const {
   return [cocoa_view_.get() window];
 }
 
 void TabContentsViewMac::GetContainerBounds(gfx::Rect* out) const {
   *out = [cocoa_view_.get() NSRectToRect:[cocoa_view_.get() bounds]];
 }
 
-void TabContentsViewMac::StartDragging(const WebDropData& drop_data,
-    WebDragOperationsMask allowed_operations) {
+void TabContentsViewMac::StartDragging(
+    const WebDropData& drop_data,
+    WebDragOperationsMask allowed_operations,
+    const SkBitmap& image,
+    const gfx::Point& image_offset) {
   // By allowing nested tasks, the code below also allows Close(),
   // which would deallocate |this|.  The same problem can occur while
   // processing -sendEvent:, so Close() is deferred in that case.
   // Drags from web content do not come via -sendEvent:, this sets the
   // same flag -sendEvent: would.
   chrome_application_mac::ScopedSendingEvent sendingEventScoper;
 
   // The drag invokes a nested event loop, arrange to continue
   // processing events.
   MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
+  // TODO(estade): make use of |image| and |image_offset|.
   NSDragOperation mask = static_cast<NSDragOperation>(allowed_operations);
   [cocoa_view_ startDragWithDropData:drop_data
                    dragOperationMask:mask];
 }
 
 void TabContentsViewMac::RenderViewCreated(RenderViewHost* host) {
   // We want updates whenever the intrinsic width of the webpage
   // changes. Put the RenderView into that mode.
   int routing_id = host->routing_id();
   host->Send(new ViewMsg_EnablePreferredSizeChangedMode(routing_id));
@@ skipping 288 matching lines @@
   [NSObject cancelPreviousPerformRequestsWithTarget:self
                                            selector:aSel
                                              object:nil];
 }
 
 - (void)closeTabAfterEvent {
   tabContentsView_->CloseTab();
 }
 
 @end