Merge 116587 - [chromium] Don't draw when canDraw() is false

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 117086)
+++ Source/WebCore/platform/graphics/chromium/cc/CCLayerTreeHostImpl.cpp	(working copy)
@@ -380,13 +380,11 @@
 bool CCLayerTreeHostImpl::prepareToDraw(FrameData& frame)
 {
     TRACE_EVENT("CCLayerTreeHostImpl::prepareToDraw", this, 0);
+    ASSERT(canDraw());
 
     frame.renderPasses.clear();
     frame.renderSurfaceLayerList.clear();
 
-    if (!m_rootLayerImpl)
-        return false;
-
     if (!calculateRenderPasses(frame.renderPasses, frame.renderSurfaceLayerList)) {
         // We're missing textures on an animating layer. Request a commit.
         m_client->setNeedsCommitOnImplThread();
@@ -405,11 +403,8 @@
 void CCLayerTreeHostImpl::drawLayers(const FrameData& frame)
 {
     TRACE_EVENT("CCLayerTreeHostImpl::drawLayers", this, 0);
-    ASSERT(m_layerRenderer);
+    ASSERT(canDraw());
 
-    if (!m_rootLayerImpl)
-        return;
-
     // FIXME: use the frame begin time from the overall compositor scheduler.
     // This value is currently inaccessible because it is up in Chromium's
     // RenderWidget.