input: Delay the dispatch of synthesized input event.

content/browser/renderer_host/input/synthetic_gesture_controller.cc

Index: content/browser/renderer_host/input/synthetic_gesture_controller.cc
diff --git a/content/browser/renderer_host/input/synthetic_gesture_controller.cc b/content/browser/renderer_host/input/synthetic_gesture_controller.cc
index 51c28aa406042f57fed6562efd9c550582f7a982..9c5fdeaa7aa8ed6a4d47a17b5630378aed63b0f3 100644
--- a/content/browser/renderer_host/input/synthetic_gesture_controller.cc
+++ b/content/browser/renderer_host/input/synthetic_gesture_controller.cc
@@ -39,9 +39,17 @@ void SyntheticGestureController::QueueSyntheticGesture(
 }
 
 void SyntheticGestureController::OnBeginFrame() {
-  // TODO(sad): Instead of dispatching the events immediately, dispatch after an
-  // offset.
-  DispatchNextEvent();
+  constexpr base::TimeDelta kSynthesizedDispatchDelay =
+      base::TimeDelta::FromMilliseconds(2);
+  base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(

[dtapuska, 2017/05/17 16:30:45]

I don't think this is quite right. Didn't we want a repeating timer? that is
sync'd on the first main frame signal?

[sadrul, 2017/05/17 18:18:01]

Yep, that's where we want to go. I am trying to take smaller steps here (1)
dispatch at (begin-frame + offset) (2) dispatch at regular intervals after the
first (begin-frame + offset), still one event per begin-frame (3) dispatch more
than one events per begin-frame. This is step 1. I am happy to go to step 2 at
the same time if you don't think taking step 1 separately is necessary (although
I should probably leave a TODO explaining the next steps).

+      FROM_HERE,
+      base::BindOnce(
+          [](base::WeakPtr<SyntheticGestureController> weak_ptr) {
+            if (weak_ptr)
+              weak_ptr->DispatchNextEvent(base::TimeTicks::Now());
+          },
+          weak_ptr_factory_.GetWeakPtr()),
+      kSynthesizedDispatchDelay);
 }
 
 bool SyntheticGestureController::DispatchNextEvent(base::TimeTicks timestamp) {