WIP GPU scheduler + delayed activation / tile draw

cc/raster/bitmap_raster_buffer_provider.cc

Index: cc/raster/bitmap_raster_buffer_provider.cc
diff --git a/cc/raster/bitmap_raster_buffer_provider.cc b/cc/raster/bitmap_raster_buffer_provider.cc
index c92d5d66c740abf1f6f6caa4cf7ce4f47d2f9551..3288b8438762576147b42e9d33cdc75e5acc3cde 100644
--- a/cc/raster/bitmap_raster_buffer_provider.cc
+++ b/cc/raster/bitmap_raster_buffer_provider.cc
@@ -102,6 +102,18 @@ void BitmapRasterBufferProvider::OrderingBarrier() {
   // No need to sync resources as this provider does not use GL context.
 }
 
+bool BitmapRasterBufferProvider::IsResourceReadyToDraw(
+    const Resource* resource) {
+  return resource;
+}
+
+void BitmapRasterBufferProvider::SignalResourcesReadyToDraw(
+    const std::vector<const Resource*>& resources,
+    const base::Closure& callback) {
+  if (!callback.is_null())
+    callback.Run();
+}
+
 ResourceFormat BitmapRasterBufferProvider::GetResourceFormat(
     bool must_support_alpha) const {
   return resource_provider_->best_texture_format();