cc: Complete swap promise for aborted commit after pending activation.

cc/trees/layer_tree_host.h

Index: cc/trees/layer_tree_host.h
diff --git a/cc/trees/layer_tree_host.h b/cc/trees/layer_tree_host.h
index 9cdc06c38420612cfa00e6914e950e0e73d836f5..81af6ad7a320a3ec0938f0bdcfab18d8ae154434 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -336,8 +336,8 @@ class CC_EXPORT LayerTreeHost : public MutatorHostClient {
   // Call this function when you expect there to be a swap buffer.
   // See swap_promise.h for how to use SwapPromise.
   void QueueSwapPromise(std::unique_ptr<SwapPromise> swap_promise);
-
   void BreakSwapPromises(SwapPromise::DidNotSwapReason reason);
+  std::vector<std::unique_ptr<SwapPromise>> TakeSwapPromises();
 
   size_t num_queued_swap_promises() const { return swap_promise_list_.size(); }