ash: Clean up system background layer.

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/auto_reset.h"
 #include "base/bind.h"
@@ skipping 385 matching lines @@
         base::Bind(&RootWindow::DispatchHeldMouseMove,
                    held_mouse_event_factory_.GetWeakPtr()));
   }
   TRACE_EVENT_ASYNC_END0("ui", "RootWindow::HoldMouseMoves", this);
 }
 
 void RootWindow::SetFocusWhenShown(bool focused) {
   host_->SetFocusWhenShown(focused);
 }
 
+bool RootWindow::CopyAreaToSkCanvas(const gfx::Rect& source_bounds,
+                                    const gfx::Point& dest_offset,
+                                    SkCanvas* canvas) {
+  DCHECK(canvas);
+  DCHECK(bounds().Contains(source_bounds));
+  gfx::Rect source_pixels = ui::ConvertRectToPixel(layer(), source_bounds);
+  return host_->CopyAreaToSkCanvas(source_pixels, dest_offset, canvas);
+}
+
 bool RootWindow::GrabSnapshot(const gfx::Rect& snapshot_bounds,
                               std::vector<unsigned char>* png_representation) {
+  DCHECK(png_representation);
   DCHECK(bounds().Contains(snapshot_bounds));
   gfx::Rect snapshot_pixels = ui::ConvertRectToPixel(layer(), snapshot_bounds);
   return host_->GrabSnapshot(snapshot_pixels, png_representation);
 }
 
 gfx::Point RootWindow::GetLastMouseLocationInRoot() const {
   gfx::Point location = Env::GetInstance()->last_mouse_location();
   client::ScreenPositionClient* client = client::GetScreenPositionClient(this);
   if (client)
     client->ConvertPointFromScreen(this, &location);
@@ skipping 599 matching lines @@
   ui::MouseEvent event(ui::ET_MOUSE_MOVED,
                        orig_mouse_location,
                        orig_mouse_location,
                        ui::EF_IS_SYNTHESIZED);
   event.set_system_location(Env::GetInstance()->last_mouse_location());
   OnHostMouseEvent(&event);
 #endif
 }
 
 }  // namespace aura