Prepare for Unified Gesture Recognizer landing in Aura

ui/events/gesture_detection/gesture_provider.cc

Index: ui/events/gesture_detection/gesture_provider.cc
diff --git a/ui/events/gesture_detection/gesture_provider.cc b/ui/events/gesture_detection/gesture_provider.cc
index 55bc37010402aad0021a62760f0a07d5d378ca89..647e71af9d691612de13708d9ed35988d95a4d64 100644
--- a/ui/events/gesture_detection/gesture_provider.cc
+++ b/ui/events/gesture_detection/gesture_provider.cc
@@ -358,8 +358,14 @@ class GestureProvider::GestureListenerImpl
     if (distance_x || distance_y) {
       GestureEventDetails scroll_details(
           ET_GESTURE_SCROLL_UPDATE, -distance_x, -distance_y);
-      provider_->Send(
-          CreateGesture(ET_GESTURE_SCROLL_UPDATE, e2, scroll_details));
+      provider_->Send(CreateGesture(ET_GESTURE_SCROLL_UPDATE,

[jdduke (slow), 2014/05/28 16:26:00]

Please cache GetBoundingBox(e2) before using.

[tdresser, 2014/05/29 14:26:21]

Done.

+                                    e2.GetId(),
+                                    e2.GetEventTime(),
+                                    GetBoundingBox(e2).CenterPoint().x(),

[jdduke (slow), 2014/05/28 16:26:00]

Just curious, why was this change necessary? Does the Aura UI not lock to a
specific layer when scrolling?

[tdresser, 2014/05/29 14:26:21]

Multi-finger window dragging uses the scroll update location delta to determine
how far to drag the window. This lets us use the same drag logic as is used for
mouse
(https://code.google.com/p/chromium/codesearch#chromium/src/ash/wm/toplevel_wi...).

[jdduke (slow), 2014/05/29 16:25:40]

sgtm.

+                                    GetBoundingBox(e2).CenterPoint().y(),
+                                    e2.GetPointerCount(),
+                                    GetBoundingBox(e2),
+                                    scroll_details));
     }
 
     return true;
@@ -650,7 +656,6 @@ void GestureProvider::Fling(const MotionEvent& event,
 }
 
 void GestureProvider::Send(const GestureEventData& gesture) {
-  DCHECK(!gesture.time.is_null());

[jdduke (slow), 2014/05/28 16:26:00]

Why was this removed?

[tdresser, 2014/05/29 14:26:21]

There are a whole pile of tests which synthesize gesture events without
assigning them a time. In theory I could go through and update all the tests,
but I don't think it's worth it.

[jdduke (slow), 2014/05/29 16:25:40]

My only worry here is that gesture detection is *very* timestamp sensitive. If
any of those tests are actually testing generated gestures, a stream of zeroed
timestamps may not yield what we want? If we don't care about the output
gestures, even a base::TimeTicks::Now() would be better so that we can at least
verify runtime behavior for Chrome builds. 

[tdresser, 2014/05/30 14:05:37]

Done.

   // The only valid events that should be sent without an active touch sequence
   // are SHOW_PRESS and TAP, potentially triggered by the double-tap
   // delay timing out.
@@ -741,8 +746,15 @@ void GestureProvider::OnTouchEventHandlingBegin(const MotionEvent& event) {
         Send(CreateGesture(ET_GESTURE_BEGIN, event));
       break;
     case MotionEvent::ACTION_POINTER_DOWN:
-      if (gesture_begin_end_types_enabled_)
-        Send(CreateGesture(ET_GESTURE_BEGIN, event));
+      if (gesture_begin_end_types_enabled_) {
+        Send(CreateGesture(ET_GESTURE_BEGIN,
+                           event.GetId(),
+                           event.GetEventTime(),
+                           event.GetX(event.GetActionIndex()),
+                           event.GetY(event.GetActionIndex()),
+                           event.GetPointerCount(),
+                           GetBoundingBox(event)));
+      }
       break;
     case MotionEvent::ACTION_POINTER_UP:
     case MotionEvent::ACTION_UP:
@@ -760,8 +772,17 @@ void GestureProvider::OnTouchEventHandlingEnd(const MotionEvent& event) {
       // |Fling()| will have already signalled an end to touch-scrolling.
       EndTouchScrollIfNecessary(event, true);
 
-      if (gesture_begin_end_types_enabled_)
-        Send(CreateGesture(ET_GESTURE_END, event));
+      if (gesture_begin_end_types_enabled_) {
+        for (size_t i = 0; i < event.GetPointerCount(); ++i) {
+          Send(CreateGesture(ET_GESTURE_END,
+                             event.GetId(),
+                             event.GetEventTime(),
+                             event.GetX(i),
+                             event.GetY(i),
+                             event.GetPointerCount() - i,
+                             GetBoundingBox(event)));

[jdduke (slow), 2014/05/28 16:26:00]

Cache GetBoundingBox?

[tdresser, 2014/05/29 14:26:21]

Done.

+        }
+      }
 
       current_down_event_.reset();