Make RenderPass::Id an isolated class

cc/trees/layer_tree_host_unittest_context.cc

Index: cc/trees/layer_tree_host_unittest_context.cc
diff --git a/cc/trees/layer_tree_host_unittest_context.cc b/cc/trees/layer_tree_host_unittest_context.cc
index 8fd9743f6d11a527018c6cab91265180ca68b2e3..9beea49050e41284e9ff3306db143f1588a70ece 100644
--- a/cc/trees/layer_tree_host_unittest_context.cc
+++ b/cc/trees/layer_tree_host_unittest_context.cc
@@ -700,18 +700,18 @@ class LayerTreeHostContextTestDontUseLostResources
     scoped_ptr<TestRenderPass> pass_for_quad = TestRenderPass::Create();
     pass_for_quad->SetNew(
         // AppendOneOfEveryQuadType() makes a RenderPass quad with this id.
-        RenderPass::Id(2, 1),
+        RenderPassId(2, 1),
         gfx::Rect(0, 0, 10, 10),
         gfx::Rect(0, 0, 10, 10),
         gfx::Transform());
 
     scoped_ptr<TestRenderPass> pass = TestRenderPass::Create();
-    pass->SetNew(RenderPass::Id(1, 1),
+    pass->SetNew(RenderPassId(1, 1),
                  gfx::Rect(0, 0, 10, 10),
                  gfx::Rect(0, 0, 10, 10),
                  gfx::Transform());
     pass->AppendOneOfEveryQuadType(child_resource_provider_.get(),
-                                   RenderPass::Id(2, 1));
+                                   RenderPassId(2, 1));
 
     frame_data->render_pass_list.push_back(pass_for_quad.PassAs<RenderPass>());
     frame_data->render_pass_list.push_back(pass.PassAs<RenderPass>());