Standardize usage of virtual/override/final in ui/

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 04763a64857ac1de0bb57f8f7e7db99fb9871103..c9ad47563b71cf2d2d53fa46a9359edaf3694e43 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -74,15 +74,15 @@ class SatisfySwapPromise : public cc::SwapPromise {
   explicit SatisfySwapPromise(uint32_t id) : id_(id) {}
 
  private:
-  virtual void DidSwap(cc::CompositorFrameMetadata* metadata) override {
+  void DidSwap(cc::CompositorFrameMetadata* metadata) override {
     metadata->satisfies_sequences.push_back(id_);
   }
 
-  virtual void DidNotSwap(DidNotSwapReason reason) override {
+  void DidNotSwap(DidNotSwapReason reason) override {
     // TODO(jbauman): Send to the SurfaceManager immediately.
     DCHECK(false);
   }
-  virtual int64 TraceId() const override { return 0; }
+  int64 TraceId() const override { return 0; }
   uint32_t id_;
 };