Eager Gesture Recognition on Aura

ui/aura/window_event_dispatcher.cc

 // Copyright 2014 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 "ui/aura/window_event_dispatcher.h"
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/client/event_client.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/client/screen_position_client.h"
 #include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_targeter.h"
 #include "ui/aura/window_tracker.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/base/hit_test.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/events/event.h"
 #include "ui/events/gestures/gesture_recognizer.h"
 #include "ui/events/gestures/gesture_types.h"
+#include "ui/events/gestures/unified_gesture_detector_enabled.h"
 
 typedef ui::EventDispatchDetails DispatchDetails;
 
 namespace aura {
 
 namespace {
 
 // Returns true if |target| has a non-client (frame) component at |location|,
 // in window coordinates.
 bool IsNonClientLocation(Window* target, const gfx::Point& location) {
@@ skipping 117 matching lines @@
     const gfx::Point& point) {
   ui::MouseEvent event(ui::ET_MOUSE_EXITED, point, point, ui::EF_NONE,
                        ui::EF_NONE);
   return DispatchMouseEnterOrExit(event, ui::ET_MOUSE_EXITED);
 }
 
 void WindowEventDispatcher::ProcessedTouchEvent(ui::TouchEvent* event,
                                                 Window* window,
                                                 ui::EventResult result) {
   scoped_ptr<ui::GestureRecognizer::Gestures> gestures;
-  gestures.reset(ui::GestureRecognizer::Get()->
-      ProcessTouchEventForGesture(*event, result, window));
+
+  if (!ui::IsUnifiedGestureDetectorEnabled()) {
+    gestures.reset(ui::GestureRecognizer::Get()->ProcessTouchEventForGesture(
+        *event, result, window));
+  } else {
+    gestures.reset(
+        ui::GestureRecognizer::Get()->AckTouchEventForGesture(result, window));
+  }
+
   DispatchDetails details = ProcessGestures(gestures.get());
   if (details.dispatcher_destroyed)
     return;
 }
 
+void WindowEventDispatcher::OnForwardingTouchEvent(ui::TouchEvent* event,
+                                                    Window* window) {
+  if (ui::IsUnifiedGestureDetectorEnabled()) {
+    ui::GestureRecognizer::Get()->ProcessTouchEventForGesture(
+        *event, event->result(), window);
+  }
+}
+
 void WindowEventDispatcher::HoldPointerMoves() {
   if (!move_hold_count_)
     held_event_factory_.InvalidateWeakPtrs();
   ++move_hold_count_;
   TRACE_EVENT_ASYNC_BEGIN0("ui", "WindowEventDispatcher::HoldPointerMoves",
                            this);
 }
 
 void WindowEventDispatcher::ReleasePointerMoves() {
   --move_hold_count_;
@@ skipping 299 matching lines @@
   DCHECK(!event_dispatch_target_ || window()->Contains(event_dispatch_target_));
 #endif
 
   if (event.IsTouchEvent() && !details.target_destroyed) {
     // Do not let 'held' touch events contribute to any gestures unless it is
     // being dispatched.
     if (dispatching_held_event_ || !held_move_event_ ||
         !held_move_event_->IsTouchEvent()) {
       ui::TouchEvent orig_event(static_cast<const ui::TouchEvent&>(event),
                                 static_cast<Window*>(event.target()), window());
-      // Get the list of GestureEvents from GestureRecognizer.
+      // If the event isn't being handled asynchronously, handle it now.
       scoped_ptr<ui::GestureRecognizer::Gestures> gestures;
       gestures.reset(ui::GestureRecognizer::Get()->
           ProcessTouchEventForGesture(orig_event, event.result(),
                                       static_cast<Window*>(target)));
+
+      if (ui::IsUnifiedGestureDetectorEnabled()) {
+        if (!(event.result() & ui::ER_CONSUMED)) {
+          gestures.reset(ui::GestureRecognizer::Get()->AckTouchEventForGesture(
+              event.result(), static_cast<Window*>(target)));
+        }
+      }

[sadrul, 2014/07/16 21:07:49]

Should this be something like:
  if (unified && !consumed) {
    gestures_.reset(AckTouchEventForGesture(....));
  else
    gestures_.reset(ProcessTouchEventForGesture(....));

to avoid creating gestures in line 508, and then discarding them in line 514?

[tdresser, 2014/07/28 18:22:09]

This issue has been addressed in the most recent patch.

       return ProcessGestures(gestures.get());
     }
   }
 
   return details;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WindowEventDispatcher, ui::GestureEventHelper implementation:
 
@@ skipping 358 matching lines @@
       break;
 
     default:
       NOTREACHED();
       break;
   }
   PreDispatchLocatedEvent(target, event);
 }
 
 }  // namespace aura