Standardize usage of virtual/override/final in cc/

cc/output/output_surface_unittest.cc

Index: cc/output/output_surface_unittest.cc
diff --git a/cc/output/output_surface_unittest.cc b/cc/output/output_surface_unittest.cc
index b70e34435b0efc062fcf110c9b13ee26f46a09cd..b1f4149196dc091a35b84370aa8f738da3a410ff 100644
--- a/cc/output/output_surface_unittest.cc
+++ b/cc/output/output_surface_unittest.cc
@@ -32,7 +32,7 @@ class TestOutputSurface : public OutputSurface {
                     scoped_ptr<SoftwareOutputDevice> software_device)
       : OutputSurface(context_provider, software_device.Pass()) {}
 
-  virtual void SwapBuffers(CompositorFrame* frame) override {
+  void SwapBuffers(CompositorFrame* frame) override {
     client_->DidSwapBuffers();
     client_->DidSwapBuffersComplete();
   }
@@ -63,11 +63,11 @@ class TestOutputSurface : public OutputSurface {
 class TestSoftwareOutputDevice : public SoftwareOutputDevice {
  public:
   TestSoftwareOutputDevice();
-  virtual ~TestSoftwareOutputDevice();
+  ~TestSoftwareOutputDevice() override;
 
   // Overriden from cc:SoftwareOutputDevice
-  virtual void DiscardBackbuffer() override;
-  virtual void EnsureBackbuffer() override;
+  void DiscardBackbuffer() override;
+  void EnsureBackbuffer() override;
 
   int discard_backbuffer_count() { return discard_backbuffer_count_; }
   int ensure_backbuffer_count() { return ensure_backbuffer_count_; }