cc: Add OutputSurface state snapshots.

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 bc2b1cb782d2fe90b45a103924f0f1fcabc54393..8c15b224fbfb50327431034c0bb9eefaa5fe8dad 100644
--- a/cc/output/direct_renderer.cc
+++ b/cc/output/direct_renderer.cc
@@ -342,6 +342,12 @@ void DirectRenderer::DrawFrame(RenderPassList* render_passes_in_draw_order,
   render_pass_background_filters_.clear();
 }
 
+void DirectRenderer::ReadbackSwappedOverlayTextures(
+    std::vector<SkBitmap>* bitmaps,
+    const base::Callback<void(bool)>& callback) {
+  callback.Run(false);
+}
+
 gfx::Rect DirectRenderer::ComputeScissorRectForRenderPass(
     const DrawingFrame* frame) {
   if (frame->current_render_pass == frame->root_render_pass)