Make RenderPass::Id an isolated class

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index 87cb2f8a8cfe4270a85f8abd9465b0c539a9a6fe..39a04ab679b6f4cf33a998a2820827f690130178 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -20,6 +20,7 @@
 #include "cc/layers/painted_scrollbar_layer_impl.h"
 #include "cc/output/copy_output_request.h"
 #include "cc/quads/debug_border_draw_quad.h"
+#include "cc/quads/render_pass.h"
 #include "cc/trees/layer_tree_host_common.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/layer_tree_settings.h"
@@ -339,13 +340,12 @@ bool LayerImpl::HasContributingDelegatedRenderPasses() const {
   return false;
 }
 
-RenderPass::Id LayerImpl::FirstContributingRenderPassId() const {
-  return RenderPass::Id(0, 0);
+RenderPassId LayerImpl::FirstContributingRenderPassId() const {
+  return RenderPassId(0, 0);
 }
 
-RenderPass::Id LayerImpl::NextContributingRenderPassId(RenderPass::Id id)
-    const {
-  return RenderPass::Id(0, 0);
+RenderPassId LayerImpl::NextContributingRenderPassId(RenderPassId id) const {
+  return RenderPassId(0, 0);
 }
 
 ResourceProvider::ResourceId LayerImpl::ContentsResourceId() const {