cc: Make --jank-instead-of-checkerboard jank more often

cc/thread_proxy.cc

Index: cc/thread_proxy.cc
diff --git a/cc/thread_proxy.cc b/cc/thread_proxy.cc
index 0dc96abb01684271e0b78566bf171424ed880b8c..307a4ec6e03a170d2a87ecbea58aaf3917fa1899 100644
--- a/cc/thread_proxy.cc
+++ b/cc/thread_proxy.cc
@@ -15,6 +15,7 @@
 #include "cc/layer_tree_host.h"
 #include "cc/scheduler.h"
 #include "cc/scoped_thread_proxy.h"
+#include "cc/settings.h"
 #include "cc/thread_task.h"
 #include <public/WebSharedGraphicsContext3D.h>
 #include <wtf/CurrentTime.h>
@@ -704,7 +705,13 @@ ScheduledActionDrawAndSwapResult ThreadProxy::scheduledActionDrawAndSwapInternal
     // prepareToDraw(), it is guarded on canDraw() as well.
 
     LayerTreeHostImpl::FrameData frame;
-    bool drawFrame = m_layerTreeHostImpl->canDraw() && (m_layerTreeHostImpl->prepareToDraw(frame) || forcedDraw);
+    bool drawFrame = false;
+    if (m_layerTreeHostImpl->canDraw()) {
+        drawFrame = m_layerTreeHostImpl->prepareToDraw(frame);
+
+        if (forcedDraw && !Settings::jankInsteadOfCheckerboard())

[danakj, 2012/10/24 20:23:39]

Is this going to break readbacks or whatever else uses forced draws?

Shouldn't we just prevent the forcedDraw from being scheduled?

[enne (OOO), 2012/10/24 20:27:35]

Done.

+            drawFrame = true;
+    }
     if (drawFrame) {
         m_layerTreeHostImpl->drawLayers(frame);
         result.didDraw = true;