Splitting DidSwap in cc::SwapPromise into WillSwap and DidSwap

cc/trees/swap_promise_manager_unittest.cc

Index: cc/trees/swap_promise_manager_unittest.cc
diff --git a/cc/trees/swap_promise_manager_unittest.cc b/cc/trees/swap_promise_manager_unittest.cc
index 9ae203702215b5aee857d8fa3045b050dce01eec..5ebd53a229698324f71836de3622a46ecd1a9752 100644
--- a/cc/trees/swap_promise_manager_unittest.cc
+++ b/cc/trees/swap_promise_manager_unittest.cc
@@ -31,7 +31,8 @@ class MockSwapPromise : public SwapPromise {
   ~MockSwapPromise() override {}
 
   void DidActivate() override {}
-  void DidSwap(CompositorFrameMetadata* metadata) override {}
+  void WillSwap(CompositorFrameMetadata* metadata) override {}
+  void DidSwap() override {}
   DidNotSwapAction DidNotSwap(DidNotSwapReason reason) override {
     return DidNotSwapAction::BREAK_PROMISE;
   }