Flip screen coordinates when converting NSEvent to WebMouseEvent. Enable proc...

chrome/browser/tab_contents/tab_contents_view_mac.mm

 // Copyright (c) 2006-2008 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.
 
 #include "chrome/browser/tab_contents/tab_contents_view_mac.h"
 
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/browser.h" // TODO(beng): this dependency is awful.
 #include "chrome/browser/cocoa/nsimage_cache.h"
 #include "chrome/browser/cocoa/sad_tab_view.h"
@@ skipping 167 matching lines @@
   }
 
   // Create an image to use for the drag.
   // TODO(pinkerton): Generate the proper image. This one will do in a pinch.
   NSImage* dragImage = nsimage_cache::ImageNamed(@"nav.pdf");
 
   NSPasteboard* pasteboard = FillDragData(drop_data);
 
   // Tell the view to start a drag using |cocoa_view_| as the drag source. The
   // source will get notified when the drag completes (success or failure) so
-  // it can tell the render view host the drag is done. Windows does this with
-  // a nested event loop, we get called back.
+  // it can tell the render view host the drag is done. The drag invokes a
+  // nested event loop, but we need to continue processing events.
   NSPoint mousePoint = [currentEvent locationInWindow];
   mousePoint = [cocoa_view_ convertPoint:mousePoint fromView:nil];
+  MessageLoop::current()->SetNestableTasksAllowed(true);
   [cocoa_view_ dragImage:dragImage
                       at:mousePoint
                   offset:NSZeroSize
                    event:currentEvent
               pasteboard:pasteboard
                   source:cocoa_view_
                slideBack:YES];
+  MessageLoop::current()->SetNestableTasksAllowed(false);
 }
 
 void TabContentsViewMac::OnContentsDestroy() {
 }
 
 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_EnableIntrinsicWidthChangedMode(routing_id));
@@ skipping 282 matching lines @@
 }
 
 - (BOOL)performDragOperation:(id<NSDraggingInfo>)sender {
   return [dropTarget_ performDragOperation:sender view:self];
 }
 
 // Tons of stuff goes here, where we grab events going on in Cocoaland and send
 // them into the C++ system. TODO(avi): all that jazz
 
 @end