cc: Add checker-imaging support to TileManager.

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index ca0f8587a82bc6c479ad0066a2876913db19e478..a8c052179dfcbaecc8d20e235b02d2701642896c 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -318,6 +318,14 @@ void LayerTreeImpl::BuildLayerListForTesting() {
   }
 }
 
+void LayerTreeImpl::InvalidateRegionForImages(
+    const std::unordered_set<uint32_t>& images_to_invalidate) {
+  DCHECK(IsSyncTree());
+  for (auto* picture_layer : picture_layers_) {

[vmpstr, 2017/02/10 19:25:43]

nit: don't need braces. I know it all seems very arbitrary, but *shrug* :)

[Khushal, 2017/02/10 22:09:19]

I think I'm understanding how this works now. :P

+    picture_layer->InvalidateRegionForImages(images_to_invalidate);
+  }
+}
+
 bool LayerTreeImpl::IsRootLayer(const LayerImpl* layer) const {
   return layer_list_.empty() ? false : layer_list_[0] == layer;
 }