Rename cc::ResourceProvider::ResourceId to cc::ResourceId and move it to its own file.

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 01a4cfd19ec4a53ace4d83314cb4c2dc60bf2774..948a80580494665d8027836c245bd4fa81a0b0ba 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -1101,8 +1101,7 @@ void LayerTreeImpl::set_ui_resource_request_queue(
   ui_resource_request_queue_ = queue;
 }
 
-ResourceProvider::ResourceId LayerTreeImpl::ResourceIdForUIResource(
-    UIResourceId uid) const {
+ResourceId LayerTreeImpl::ResourceIdForUIResource(UIResourceId uid) const {
   return layer_tree_host_impl_->ResourceIdForUIResource(uid);
 }