1 files changed, 19 insertions, 0 deletions
diff --git a/Source/WebKit2/UIProcess/DrawingAreaProxyImpl.cpp b/Source/WebKit2/UIProcess/DrawingAreaProxyImpl.cpp
index 6519441b0..0fd295dcc 100644
--- a/Source/WebKit2/UIProcess/DrawingAreaProxyImpl.cpp
+++ b/Source/WebKit2/UIProcess/DrawingAreaProxyImpl.cpp
@@ -245,6 +245,17 @@ void DrawingAreaProxyImpl::exitAcceleratedCompositingMode(uint64_t backingStoreS
     incorporateUpdate(updateInfo);
 }
 
+void DrawingAreaProxyImpl::updateAcceleratedCompositingMode(uint64_t backingStoreStateID, const LayerTreeContext& layerTreeContext)
+{
+    ASSERT_ARG(backingStoreStateID, backingStoreStateID <= m_currentBackingStoreStateID);
+    if (backingStoreStateID < m_currentBackingStoreStateID)
+        return;
+
+#if USE(ACCELERATED_COMPOSITING)
+    updateAcceleratedCompositingMode(layerTreeContext);
+#endif
+}
+
 void DrawingAreaProxyImpl::incorporateUpdate(const UpdateInfo& updateInfo)
 {
     ASSERT(!isInAcceleratedCompositingMode());
@@ -368,6 +379,14 @@ void DrawingAreaProxyImpl::exitAcceleratedCompositingMode()
     m_layerTreeContext = LayerTreeContext();    
     m_webPageProxy->exitAcceleratedCompositingMode();
 }
+
+void DrawingAreaProxyImpl::updateAcceleratedCompositingMode(const LayerTreeContext& layerTreeContext)
+{
+    ASSERT(isInAcceleratedCompositingMode());
+
+    m_layerTreeContext = layerTreeContext;
+    m_webPageProxy->updateAcceleratedCompositingMode(layerTreeContext);
+}
 #endif
 
 void DrawingAreaProxyImpl::pageCustomRepresentationChanged()