views: Extract Widget observer into its own header file.

ui/views/view.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/views/view.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
@@ skipping 710 matching lines @@
     return;
 
   // Non-empty clip, translate the graphics such that 0,0 corresponds to
   // where this view is located (related to its parent).
   canvas->Translate(GetMirroredPosition());
   canvas->Transform(GetTransform());
 
   PaintCommon(canvas);
 }
 
-ThemeProvider* View::GetThemeProvider() const {
+ui::ThemeProvider* View::GetThemeProvider() const {
   const Widget* widget = GetWidget();
   return widget ? widget->GetThemeProvider() : NULL;
 }
 
 // Accelerated Painting --------------------------------------------------------
 
 // static
 void View::set_use_acceleration_when_possible(bool use) {
   use_acceleration_when_possible = use;
 }
@@ skipping 1364 matching lines @@
   gfx::Point widget_location(event.location());
   ConvertPointToWidget(this, &widget_location);
   GetWidget()->RunShellDrag(this, data, widget_location, drag_operations);
   return true;
 #else
   return false;
 #endif  // !defined(OS_MACOSX)
 }
 
 }  // namespace views