Aura desktop: Fix tab dragging within a single chrome window.

ui/aura/root_window.cc

 // 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.
 
 #include "ui/aura/root_window.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 141 matching lines @@
   // cleared and we don't hit asserts.
   compositor_.reset();
 
   // Tear down in reverse.  Frees any references held by the host.
   host_.reset(NULL);
 
   // An observer may have been added by an animation on the RootWindow.
   layer()->GetAnimator()->RemoveObserver(this);
 }
 
+// static
+RootWindow* RootWindow::GetForAcceleratedWidget(
+    gfx::AcceleratedWidget widget) {
+  RootWindowHost* host = RootWindowHost::GetForAcceleratedWidget(widget);
+  return host ? host->GetRootWindow() : NULL;
+}
+
 void RootWindow::Init() {
   compositor()->SetScaleAndSize(GetDeviceScaleFactorFromMonitor(this),
                                 host_->GetBounds().size());
   Window::Init(ui::LAYER_NOT_DRAWN);
   last_mouse_location_ =
       ui::ConvertPointToDIP(layer(), host_->QueryMouseLocation());
   compositor()->SetRootLayer(layer());
   SetBounds(
       ui::ConvertRectToDIP(layer(), gfx::Rect(host_->GetBounds().size())));
   Show();
@@ skipping 860 matching lines @@
 void RootWindow::UnlockCompositor() {
   DCHECK(compositor_lock_);
   compositor_lock_ = NULL;
   if (draw_on_compositor_unlock_) {
     draw_on_compositor_unlock_ = false;
     ScheduleDraw();
   }
 }
 
 }  // namespace aura