input: Fix running the completion callback for telemetry gesture.

content/browser/renderer_host/input/synthetic_gesture_controller.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/renderer_host/input/synthetic_gesture_controller.h"
 
 #include <utility>
 
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/trace_event.h"
 #include "content/browser/renderer_host/input/synthetic_gesture_target.h"
 #include "content/common/input/synthetic_smooth_scroll_gesture_params.h"
 #include "content/common/input_messages.h"
 #include "content/public/browser/render_widget_host.h"
 
 namespace content {
 
 SyntheticGestureController::SyntheticGestureController(
-    std::unique_ptr<SyntheticGestureTarget> gesture_target,
-    BeginFrameRequestCallback begin_frame_callback)
-    : gesture_target_(std::move(gesture_target)),
-      begin_frame_callback_(std::move(begin_frame_callback)),
-      weak_ptr_factory_(this) {}
+    Delegate* delegate,
+    std::unique_ptr<SyntheticGestureTarget> gesture_target)
+    : delegate_(delegate),
+      gesture_target_(std::move(gesture_target)),
+      weak_ptr_factory_(this) {
+  DCHECK(delegate_);
+}
 
 SyntheticGestureController::~SyntheticGestureController() {}
 
 void SyntheticGestureController::QueueSyntheticGesture(
     std::unique_ptr<SyntheticGesture> synthetic_gesture,
     const OnGestureCompleteCallback& completion_callback) {
   DCHECK(synthetic_gesture);
 
   bool was_empty = pending_gesture_queue_.IsEmpty();
 
   pending_gesture_queue_.Push(std::move(synthetic_gesture),
                               completion_callback);
 
   if (was_empty)
     StartGesture(*pending_gesture_queue_.FrontGesture());
 }
 
+void SyntheticGestureController::RequestBeginFrame() {
+  delegate_->RequestBeginFrameForSynthesizedInput(
+      base::BindOnce(&SyntheticGestureController::OnBeginFrame,
+                     weak_ptr_factory_.GetWeakPtr()));
+}
+
 void SyntheticGestureController::OnBeginFrame() {
   // TODO(sad): Instead of dispatching the events immediately, dispatch after an
   // offset.
   DispatchNextEvent();
 }
 
 bool SyntheticGestureController::DispatchNextEvent(base::TimeTicks timestamp) {
   TRACE_EVENT0("input", "SyntheticGestureController::Flush");
   if (pending_gesture_queue_.IsEmpty())
     return false;
 
-  SyntheticGesture::Result result =
-      pending_gesture_queue_.FrontGesture()->ForwardInputEvents(
-          timestamp, gesture_target_.get());
+  if (!pending_gesture_queue_.is_current_gesture_complete()) {
+    SyntheticGesture::Result result =
+        pending_gesture_queue_.FrontGesture()->ForwardInputEvents(
+            timestamp, gesture_target_.get());
 
-  if (result == SyntheticGesture::GESTURE_RUNNING) {
-    begin_frame_callback_.Run(
-        base::BindOnce(&SyntheticGestureController::OnBeginFrame,
-                       weak_ptr_factory_.GetWeakPtr()));
+    if (result == SyntheticGesture::GESTURE_RUNNING) {
+      RequestBeginFrame();
+      return true;
+    }
+    pending_gesture_queue_.mark_current_gesture_complete(result);
+  }
+
+  if (!delegate_->HasGestureStopped()) {
+    RequestBeginFrame();

[dtapuska, 2017/05/19 13:20:36]

This will still add an additional frame of latency to the gesture event right?

tdresser@ we don't really care about this too much right? (ie; we don't use the
completion callback for anything other than possibly running the next gesture or
checking the state of things)

[tdresser, 2017/05/19 13:53:32]

Yup, this should be fine.

[sadrul, 2017/05/19 16:55:49]

This will add at most one frame to the end of the gesture, correct. But it
should not affect the metrics we would normally care about (e.g. queuing
latency, first-update etc.) I believe.

And this also affects the start of the next gesture, but I don't think that
would affect the metrics. It can add one frame to the test duration, but that
should be ok.

     return true;
   }
 
   StopGesture(*pending_gesture_queue_.FrontGesture(),
-              pending_gesture_queue_.FrontCallback(), result);
+              pending_gesture_queue_.FrontCallback(),
+              pending_gesture_queue_.current_gesture_result());
   pending_gesture_queue_.Pop();
   if (pending_gesture_queue_.IsEmpty())
     return false;
   StartGesture(*pending_gesture_queue_.FrontGesture());
   return true;
 }
 
 void SyntheticGestureController::StartGesture(const SyntheticGesture& gesture) {
   TRACE_EVENT_ASYNC_BEGIN0("input,benchmark",
                            "SyntheticGestureController::running",
                            &gesture);
-  begin_frame_callback_.Run(
-      base::BindOnce(&SyntheticGestureController::OnBeginFrame,
-                     weak_ptr_factory_.GetWeakPtr()));
+  RequestBeginFrame();
 }
 
 void SyntheticGestureController::StopGesture(
     const SyntheticGesture& gesture,
     const OnGestureCompleteCallback& completion_callback,
     SyntheticGesture::Result result) {
   DCHECK_NE(result, SyntheticGesture::GESTURE_RUNNING);
   TRACE_EVENT_ASYNC_END0("input,benchmark",
                          "SyntheticGestureController::running",
                          &gesture);
 
   completion_callback.Run(result);
 }
 
 SyntheticGestureController::GestureAndCallbackQueue::GestureAndCallbackQueue() {
 }
 
 SyntheticGestureController::GestureAndCallbackQueue::
     ~GestureAndCallbackQueue() {
 }
 
 }  // namespace content