[cc] Store CCLayerImpls as scoped_ptrs

cc/CCLayerTreeHostImpl.cpp

 // Copyright 2011 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 "config.h"
 
 #include "CCLayerTreeHostImpl.h"
 
 #include "base/basictypes.h"
 #include "CCAppendQuadsData.h"
@@ skipping 767 matching lines @@
 
     if (layerImpl->scrollable())
         return layerImpl;
 
     if (layerImpl->drawsContent() && layerImpl->parent() && layerImpl->parent()->scrollable())
         return layerImpl->parent();
 
     return 0;
 }
 
-void CCLayerTreeHostImpl::setRootLayer(PassOwnPtr<CCLayerImpl> layer)
+void CCLayerTreeHostImpl::setRootLayer(scoped_ptr<CCLayerImpl> layer)
 {
-    m_rootLayerImpl = layer;
+    m_rootLayerImpl = layer.Pass();
     m_rootScrollLayerImpl = findRootScrollLayer(m_rootLayerImpl.get());
     m_currentlyScrollingLayerImpl = 0;
 
     if (m_rootLayerImpl && m_scrollingLayerIdFromPreviousTree != -1)
         m_currentlyScrollingLayerImpl = CCLayerTreeHostCommon::findLayerInSubtree(m_rootLayerImpl.get(), m_scrollingLayerIdFromPreviousTree);
 
     m_scrollingLayerIdFromPreviousTree = -1;
 
     m_client->onCanDrawStateChanged(canDraw());
 }
 
-PassOwnPtr<CCLayerImpl> CCLayerTreeHostImpl::detachLayerTree()
+scoped_ptr<CCLayerImpl> CCLayerTreeHostImpl::detachLayerTree()
 {
     // Clear all data structures that have direct references to the layer tree.
     m_scrollingLayerIdFromPreviousTree = m_currentlyScrollingLayerImpl ? m_currentlyScrollingLayerImpl->id() : -1;
     m_currentlyScrollingLayerImpl = 0;
     m_renderSurfaceLayerList.clear();
 
-    return m_rootLayerImpl.release();
+    return m_rootLayerImpl.Pass();
 }
 
 void CCLayerTreeHostImpl::setVisible(bool visible)
 {
     ASSERT(CCProxy::isImplThread());
 
     if (m_visible == visible)
         return;
     m_visible = visible;
     didVisibilityChange(this, m_visible);
@@ skipping 633 matching lines @@
 
     CCScrollbarAnimationController* scrollbarController = layer->scrollbarAnimationController();
     if (scrollbarController && scrollbarController->animate(monotonicTime))
         m_client->setNeedsRedrawOnImplThread();
 
     for (size_t i = 0; i < layer->children().size(); ++i)
         animateScrollbarsRecursive(layer->children()[i], monotonicTime);
 }
 
 }  // namespace cc