Make cc::SurfaceId unguessable

cc/surfaces/surface_factory_unittest.cc

Index: cc/surfaces/surface_factory_unittest.cc
diff --git a/cc/surfaces/surface_factory_unittest.cc b/cc/surfaces/surface_factory_unittest.cc
index 1d7a8b92d669b85612df04d8fcce3d0b19bb5f4d..24a5a7a1c0e71874846531d87e066232f94156c8 100644
--- a/cc/surfaces/surface_factory_unittest.cc
+++ b/cc/surfaces/surface_factory_unittest.cc
@@ -58,7 +58,7 @@ class TestSurfaceFactoryClient : public SurfaceFactoryClient {
 class SurfaceFactoryTest : public testing::Test {
  public:
   SurfaceFactoryTest()
-      : factory_(new SurfaceFactory(&manager_, &client_)), surface_id_(3) {
+      : factory_(new SurfaceFactory(&manager_, &client_)), surface_id_(0, 3) {
     factory_->Create(surface_id_);
   }
 
@@ -389,7 +389,7 @@ TEST_F(SurfaceFactoryTest, ResourceLifetime) {
 }
 
 TEST_F(SurfaceFactoryTest, BlankNoIndexIncrement) {
-  SurfaceId surface_id(6);
+  SurfaceId surface_id(0, 6);
   factory_->Create(surface_id);
   Surface* surface = manager_.GetSurfaceForId(surface_id);
   ASSERT_NE(nullptr, surface);
@@ -412,7 +412,7 @@ void DrawCallback(uint32_t* execute_count,
 
 // Tests doing a DestroyAll before shutting down the factory;
 TEST_F(SurfaceFactoryTest, DestroyAll) {
-  SurfaceId id(7);
+  SurfaceId id(0, 7);
   factory_->Create(id);
 
   std::unique_ptr<DelegatedFrameData> frame_data(new DelegatedFrameData);
@@ -435,7 +435,7 @@ TEST_F(SurfaceFactoryTest, DestroyAll) {
 }
 
 TEST_F(SurfaceFactoryTest, DestroySequence) {
-  SurfaceId id2(5);
+  SurfaceId id2(0, 5);
   factory_->Create(id2);
 
   manager_.RegisterSurfaceIdNamespace(0);
@@ -468,7 +468,7 @@ TEST_F(SurfaceFactoryTest, DestroySequence) {
 // Sequences to be ignored.
 TEST_F(SurfaceFactoryTest, InvalidIdNamespace) {
   uint32_t id_namespace = 9u;
-  SurfaceId id(5);
+  SurfaceId id(id_namespace, 5);
   factory_->Create(id);
 
   manager_.RegisterSurfaceIdNamespace(id_namespace);
@@ -487,7 +487,7 @@ TEST_F(SurfaceFactoryTest, InvalidIdNamespace) {
 }
 
 TEST_F(SurfaceFactoryTest, DestroyCycle) {
-  SurfaceId id2(5);
+  SurfaceId id2(0, 5);
   factory_->Create(id2);
 
   manager_.RegisterSurfaceIdNamespace(0);