Move visual rect unioning between paired items to cc::DisplayItemList.

ui/compositor/transform_recorder.h

 // Copyright 2015 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.
 
 #ifndef UI_COMPOSITOR_TRANSFORM_RECORDER_H_
 #define UI_COMPOSITOR_TRANSFORM_RECORDER_H_
 
 #include "base/macros.h"
 #include "ui/compositor/compositor_export.h"
-#include "ui/gfx/geometry/rect.h"
 
 namespace cc {
 class DisplayItem;
 class DisplayItemList;
 }
 
 namespace gfx {
-class Size;
 class Transform;
 }
 
 namespace ui {
 class PaintContext;
 
 // A class to provide scoped transforms of painting to a DisplayItemList. The
 // transform provided will be applied to any DisplayItems added to the
 // DisplayItemList while this object is alive. In other words, any nested
 // recorders will be transformed.
 class COMPOSITOR_EXPORT TransformRecorder {
  public:
   explicit TransformRecorder(const PaintContext& context);
   ~TransformRecorder();
 
-  // |size_in_context| is the size in the paint context's space surrounding
-  // everything that's visible.
-  void Transform(const gfx::Transform& transform,
-                 const gfx::Size& size_in_context);
+  void Transform(const gfx::Transform& transform);
 
  private:
   const PaintContext& context_;
-  gfx::Rect bounds_in_layer_;
   bool transformed_;
 
   DISALLOW_COPY_AND_ASSIGN(TransformRecorder);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_TRANSFORM_RECORDER_H_