cc: Add readback and forced draw states to the Scheduler

cc/output/direct_renderer.cc

Index: cc/output/direct_renderer.cc
diff --git a/cc/output/direct_renderer.cc b/cc/output/direct_renderer.cc
index 15f8501ff97f91f516e9d6692bfb68c025216364..9d5cd242f1967bf5c5f62f00914baded686e7d75 100644
--- a/cc/output/direct_renderer.cc
+++ b/cc/output/direct_renderer.cc
@@ -135,7 +135,9 @@ DirectRenderer::DirectRenderer(RendererClient* client,
 
 DirectRenderer::~DirectRenderer() {}
 
-bool DirectRenderer::CanReadPixels() const { return true; }
+bool DirectRenderer::CanReadPixels() const {
+  return !output_surface_->IsLost();

[brianderson, 2013/09/06 21:43:15]

This hopefully fixes the mac_rel failure when losing the context in the middle
of a readback by just failing the readback.

[danakj, 2013/09/06 21:45:57]

This is kinda abuse of this method. It's really meant like "is this renderer
capable of reading pixels", not checking on states. Can this be done outside the
renderer?

+}
 
 void DirectRenderer::SetEnlargePassTextureAmountForTesting(
     gfx::Vector2d amount) {