Merge 121450 - [chromium] Should schedule a commit when dropping contents textures

Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostImpl.cpp

Index: Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostImpl.cpp
===================================================================
--- Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostImpl.cpp	(revision 122259)
+++ Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostImpl.cpp	(working copy)
@@ -156,6 +156,7 @@
 
 void CCLayerTreeHostImpl::commitComplete()
 {
+    TRACE_EVENT0("cc", "CCLayerTreeHostImpl::commitComplete");
     // Recompute max scroll position; must be after layer content bounds are
     // updated.
     updateMaxScrollPosition();
@@ -164,14 +165,22 @@
 
 bool CCLayerTreeHostImpl::canDraw()
 {
-    if (!m_rootLayerImpl)
+    if (!m_rootLayerImpl) {
+        TRACE_EVENT_INSTANT0("cc", "CCLayerTreeHostImpl::canDraw no root layer");
         return false;
-    if (viewportSize().isEmpty())
+    }
+    if (viewportSize().isEmpty()) {
+        TRACE_EVENT_INSTANT0("cc", "CCLayerTreeHostImpl::canDraw empty viewport");
         return false;
-    if (!m_layerRenderer)
+    }
+    if (!m_layerRenderer) {
+        TRACE_EVENT_INSTANT0("cc", "CCLayerTreeHostImpl::canDraw no layerRenderer");
         return false;
-    if (m_contentsTexturesWerePurgedSinceLastCommit)
+    }
+    if (m_contentsTexturesWerePurgedSinceLastCommit) {
+        TRACE_EVENT_INSTANT0("cc", "CCLayerTreeHostImpl::canDraw contents textures purged");
         return false;
+    }
     return true;
 }
 
@@ -409,6 +418,7 @@
 {
     contentsTextureAllocator()->deleteAllTextures();
     m_contentsTexturesWerePurgedSinceLastCommit = true;
+    m_client->setNeedsCommitOnImplThread();
 }
 
 void CCLayerTreeHostImpl::setMemoryAllocationLimitBytes(size_t bytes)