cc: Add testing stubs for proxy test

cc/test/layer_tree_test.cc

Index: cc/test/layer_tree_test.cc
diff --git a/cc/test/layer_tree_test.cc b/cc/test/layer_tree_test.cc
index 5c85d160670ea09459dbc904a343a6d0fbccda96..a83013ff25f4beace303e075a40f749c9d41d8f4 100644
--- a/cc/test/layer_tree_test.cc
+++ b/cc/test/layer_tree_test.cc
@@ -25,6 +25,7 @@
 #include "cc/trees/layer_tree_host_single_thread_client.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/single_thread_proxy.h"
+#include "cc/trees/thread_proxy.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "ui/gfx/frame_time.h"
 #include "ui/gfx/size_conversions.h"
@@ -46,6 +47,33 @@ base::TimeDelta TestHooks::LowFrequencyAnimationInterval() const {
   return base::TimeDelta::FromMilliseconds(16);
 }
 
+// Adapts ThreadProxy for test. Injects test hooks for testing.
+class ThreadProxyForTest : public ThreadProxy {
+ public:
+  static scoped_ptr<Proxy> Create(
+      TestHooks* test_hooks,
+      LayerTreeHost* host,
+      scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner) {
+    return make_scoped_ptr(
+        new ThreadProxyForTest(test_hooks,
+                               host,
+                               impl_task_runner)).PassAs<Proxy>();
+  }
+
+  virtual ~ThreadProxyForTest() {}
+
+ private:
+  TestHooks* test_hooks_;
+
+  ThreadProxyForTest(
+      TestHooks* test_hooks,
+      LayerTreeHost* host,
+      scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner)
+      : ThreadProxy(host, impl_task_runner),
+        test_hooks_(test_hooks) {
+  }
+};
+
 // Adapts LayerTreeHostImpl for test. Runs real code, then invokes test hooks.
 class LayerTreeHostImplForTesting : public LayerTreeHostImpl {
  public:
@@ -320,6 +348,12 @@ class LayerTreeHostForTesting : public LayerTreeHost {
 
   virtual void DidDeferCommit() OVERRIDE { test_hooks_->DidDeferCommit(); }
 
+  virtual void InitializeThreaded(
+      scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner) OVERRIDE {
+    InitializeProxy(
+        ThreadProxyForTest::Create(test_hooks_, this, impl_task_runner));
+  }
+
  private:
   LayerTreeHostForTesting(TestHooks* test_hooks,
                           LayerTreeHostClient* client,