Reusing base::IdType<...> to implement SurfaceId.

cc/surfaces/surface_unittest.cc

Index: cc/surfaces/surface_unittest.cc
diff --git a/cc/surfaces/surface_unittest.cc b/cc/surfaces/surface_unittest.cc
index 5a9b744fd75dc320129d0be30ac106f4673fb65f..31df308a9a24be497cd2d1cbd2de47c6d2d4aa2f 100644
--- a/cc/surfaces/surface_unittest.cc
+++ b/cc/surfaces/surface_unittest.cc
@@ -35,7 +35,7 @@ TEST(SurfaceTest, SurfaceLifetime) {
   FakeSurfaceFactoryClient surface_factory_client;
   SurfaceFactory factory(&manager, &surface_factory_client);
 
-  SurfaceId surface_id(6);
+  SurfaceId surface_id = SurfaceId::FromUnsafeValue(6);
   {
     factory.Create(surface_id);
     EXPECT_TRUE(manager.GetSurfaceForId(surface_id));
@@ -50,7 +50,7 @@ TEST(SurfaceTest, StableBeginFrameSourceIndependentOfOrderAdded) {
   FakeSurfaceFactoryClient surface_factory_client;
   SurfaceFactory factory(&manager, &surface_factory_client);
 
-  SurfaceId surface_id(6);
+  SurfaceId surface_id = SurfaceId::FromUnsafeValue(6);
   factory.Create(surface_id);
   Surface* surface = manager.GetSurfaceForId(surface_id);
 
@@ -138,7 +138,7 @@ TEST(SurfaceTest, BeginFrameSourceRemovedOnSurfaceDestruction) {
   SurfaceFactory factory(&manager, &surface_factory_client);
   FakeBeginFrameSource bfs;
 
-  SurfaceId surface_id(6);
+  SurfaceId surface_id = SurfaceId::FromUnsafeValue(6);
   factory.Create(surface_id);
   Surface* surface = manager.GetSurfaceForId(surface_id);
   surface->AddBeginFrameSource(&bfs);