Added an assertion verifying that a Canvas2DLayerBridge is not deleted

when still in the Canvas2DLayerManager list.

In order to be able to call Canvas2DLayerManager::isInList,
the method has been changed from private to public.

BUG=385141

Review URL: https://codereview.chromium.org/340093003

git-svn-id: svn://svn.chromium.org/blink/trunk@176442 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/platform/graphics/Canvas2DLayerBridge.cpp

@@ -116,6 +116,7 @@ Canvas2DLayerBridge::Canvas2DLayerBridge(PassOwnPtr<blink::WebGraphicsContext3DP
 Canvas2DLayerBridge::~Canvas2DLayerBridge()
 {
     ASSERT(m_destructionInProgress);
+    ASSERT(!Canvas2DLayerManager::get().isInList(this));
     m_layer.clear();
     freeReleasedMailbox();
 #if ASSERT_ENABLED

third_party/WebKit/Source/platform/graphics/Canvas2DLayerManager.h

@@ -42,12 +42,12 @@ public:
     void layerTransientResourceAllocationChanged(Canvas2DLayerBridge*, intptr_t deltaBytes = 0);
     void layerDidDraw(Canvas2DLayerBridge*);
 
+    bool isInList(Canvas2DLayerBridge*) const;
 private:
     Canvas2DLayerManager();
 
     // internal methods
     void freeMemoryIfNecessary();
-    bool isInList(Canvas2DLayerBridge*) const;
     void addLayerToList(Canvas2DLayerBridge*);
     void removeLayerFromList(Canvas2DLayerBridge*);
     virtual void willProcessTask() OVERRIDE;