Use LatencyInfoSwapPromise to track LatencyInfo through compositor

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index e7dfa970476efa4bb816e22f4378d0b57dedb06a..bf40e0c97caa94abebc2bf30d891f8596c2acf40 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -5233,7 +5233,8 @@ struct TestSwapPromiseResult {
 class TestSwapPromise : public SwapPromise {
  public:
   explicit TestSwapPromise(TestSwapPromiseResult* result)
-      : result_(result) {
+      : SwapPromise(SWAP_PROMISE_UNKNOWN),
+        result_(result) {
   }
 
   virtual ~TestSwapPromise() {
@@ -5241,7 +5242,7 @@ class TestSwapPromise : public SwapPromise {
     result_->dtor_called = true;
   }
 
-  virtual void DidSwap() OVERRIDE {
+  virtual void DidSwap(CompositorFrameMetadata* metadata) OVERRIDE {
     base::AutoLock lock(result_->lock);
     EXPECT_FALSE(result_->did_swap_called);
     EXPECT_FALSE(result_->did_not_swap_called);