Add Vector2d classes that represent offsets, instead of using Point.

content/browser/web_contents/web_contents_view_mac.mm

 // Copyright (c) 2012 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>
 
 #import "content/browser/web_contents/web_contents_view_mac.h"
 
 #include <string>
 
@@ skipping 156 matching lines @@
   NSScreen* screen = [[NSScreen screens] objectAtIndex:0];
   bounds.origin.y = [screen frame].size.height - bounds.origin.y
       - bounds.size.height;
   *out = gfx::Rect(NSRectToCGRect(bounds));
 }
 
 void WebContentsViewMac::StartDragging(
     const WebDropData& drop_data,
     WebDragOperationsMask allowed_operations,
     const gfx::ImageSkia& image,
-    const gfx::Point& image_offset) {
+    const gfx::Vector2d& 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.
   base::mac::ScopedSendingEvent sending_event_scoper;
 
   // The drag invokes a nested event loop, arrange to continue
   // processing events.
   MessageLoop::ScopedNestableTaskAllower allow(MessageLoop::current());
   NSDragOperation mask = static_cast<NSDragOperation>(allowed_operations);
-  NSPoint offset = NSPointFromCGPoint(image_offset.ToCGPoint());
+  NSPoint offset = NSPointFromCGPoint(
+      gfx::PointAtOffsetFromOrigin(image_offset).ToCGPoint());
   [cocoa_view_ startDragWithDropData:drop_data
                    dragOperationMask:mask
                                image:gfx::NSImageFromImageSkia(image)
                               offset:offset];
 }
 
 void WebContentsViewMac::RenderViewCreated(RenderViewHost* host) {
   // We want updates whenever the intrinsic width of the webpage changes.
   // Put the RenderView into that mode. The preferred width is used for example
   // when the "zoom" button in the browser window is clicked.
@@ skipping 331 matching lines @@
       [[[notification userInfo] objectForKey:kSelectionDirection]
         unsignedIntegerValue];
   if (direction == NSDirectSelection)
     return;
 
   [self webContents]->
       FocusThroughTabTraversal(direction == NSSelectingPrevious);
 }
 
 @end