Reland "Fling bubbles from OOPIF properly" without the tests.

This cl relands the following cl after excluding the added tests.
https://chromium-review.googlesource.com/c/chromium/src/+/1278963

This gives the solution more time to bake on ToT without getting
reverted due to flaky tests.

Meanwhile I will work on the tests to deflake them.

TBR=mcnee@chromium.org,creis@chromium.org

Bug: 884728, 249063
Change-Id: Icc1e32ffe493f85d0ee74b0aff37ccdf078d0e8f
Reviewed-on: https://chromium-review.googlesource.com/c/1281687
Commit-Queue: Charlie Reis <creis@chromium.org>
Reviewed-by: Kevin McNee <mcnee@chromium.org>
Reviewed-by: Charlie Reis <creis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599781}

content/browser/frame_host/cross_process_frame_connector.cc

@@ -279,7 +279,8 @@ void CrossProcessFrameConnector::BubbleScrollEvent(
   DCHECK(event.GetType() == blink::WebInputEvent::kGestureScrollBegin ||
          event.GetType() == blink::WebInputEvent::kGestureScrollUpdate ||
          event.GetType() == blink::WebInputEvent::kGestureScrollEnd ||
-         event.GetType() == blink::WebInputEvent::kGestureFlingStart);
+         event.GetType() == blink::WebInputEvent::kGestureFlingStart ||
+         event.GetType() == blink::WebInputEvent::kGestureFlingCancel);
   auto* parent_view = GetParentRenderWidgetHostView();
 
   if (!parent_view)
@@ -302,7 +303,9 @@ void CrossProcessFrameConnector::BubbleScrollEvent(
   if (event.GetType() == blink::WebInputEvent::kGestureScrollBegin) {
     event_router->BubbleScrollEvent(parent_view, resent_gesture_event, view_);
     is_scroll_bubbling_ = true;
-  } else if (is_scroll_bubbling_) {
+  } else if (is_scroll_bubbling_ ||
+             event.GetType() == blink::WebInputEvent::kGestureFlingCancel) {
+    // For GFC events the router decides whether to bubble them or not.
     event_router->BubbleScrollEvent(parent_view, resent_gesture_event, view_);
   }
   if (event.GetType() == blink::WebInputEvent::kGestureScrollEnd ||

content/browser/renderer_host/render_widget_host_input_event_router.cc

@@ -294,6 +294,9 @@ void RenderWidgetHostInputEventRouter::OnRenderWidgetHostViewBaseDestroyed(
   if (view == last_fling_start_target_)
     last_fling_start_target_ = nullptr;
 
+  if (view == last_fling_start_bubbled_target_)
+    last_fling_start_bubbled_target_ = nullptr;
+
   event_targeter_->ViewWillBeDestroyed(view);
 }
 
@@ -1002,7 +1005,8 @@ void RenderWidgetHostInputEventRouter::BubbleScrollEvent(
   DCHECK(event.GetType() == blink::WebInputEvent::kGestureScrollBegin ||
          event.GetType() == blink::WebInputEvent::kGestureScrollUpdate ||
          event.GetType() == blink::WebInputEvent::kGestureScrollEnd ||
-         event.GetType() == blink::WebInputEvent::kGestureFlingStart);
+         event.GetType() == blink::WebInputEvent::kGestureFlingStart ||
+         event.GetType() == blink::WebInputEvent::kGestureFlingCancel);
 
   ui::LatencyInfo latency_info =
       ui::WebInputEventTraits::CreateLatencyInfoForWebGestureEvent(event);
@@ -1031,7 +1035,26 @@ void RenderWidgetHostInputEventRouter::BubbleScrollEvent(
     }
 
     bubbling_gesture_scroll_target_.target = target_view;
+  } else if (event.GetType() == blink::WebInputEvent::kGestureFlingCancel) {
+    // TODO(828422): Remove once this issue no longer occurs.
+    if (resending_view == last_fling_start_bubbled_target_) {
+      ReportBubblingScrollToSameView(event, resending_view);
+      last_fling_start_bubbled_target_ = nullptr;
+      return;
+    }
+    // GFC event must get bubbled to the same target view that the last GFS has
+    // been bubbled.
+    if (last_fling_start_bubbled_target_) {
+      last_fling_start_bubbled_target_->ProcessGestureEvent(
+          GestureEventInTarget(event, last_fling_start_bubbled_target_),
+          latency_info);
+      last_fling_start_bubbled_target_ = nullptr;
+    }
+    return;
   } else {  // !(event.GetType() == blink::WebInputEvent::kGestureScrollBegin)
+            // && !(event.GetType() ==
+            // blink::WebInputEvent::kGestureFlingCancel)
+
     if (!bubbling_gesture_scroll_target_.target) {
       // The GestureScrollBegin event is not bubbled, don't bubble the rest of
       // the scroll events.
@@ -1063,6 +1086,12 @@ void RenderWidgetHostInputEventRouter::BubbleScrollEvent(
   bubbling_gesture_scroll_target_.target->ProcessGestureEvent(
       GestureEventInTarget(event, bubbling_gesture_scroll_target_.target),
       latency_info);
+
+  // The GFC should be sent to the view that handles the GFS.
+  if (event.GetType() == blink::WebInputEvent::kGestureFlingStart) {
+    last_fling_start_bubbled_target_ = bubbling_gesture_scroll_target_.target;
+  }
+
   if (event.GetType() == blink::WebInputEvent::kGestureScrollEnd ||
       event.GetType() == blink::WebInputEvent::kGestureFlingStart) {
     first_bubbling_scroll_target_.target = nullptr;

content/browser/renderer_host/render_widget_host_input_event_router.h

@@ -317,6 +317,12 @@ class CONTENT_EXPORT RenderWidgetHostInputEventRouter
   // Tracked for the purpose of targeting subsequent fling cancel events.
   RenderWidgetHostViewBase* last_fling_start_target_ = nullptr;
 
+  // During scroll bubbling we bubble the GFS to the target view so that its
+  // fling controller takes care of flinging. In this case we should also send
+  // the GFC to the bubbling target so that the fling controller currently in
+  // charge of the fling progress could handle the fling cancellelation as well.
+  RenderWidgetHostViewBase* last_fling_start_bubbled_target_ = nullptr;
+
   // Tracked for the purpose of providing a root_view when dispatching emulated
   // touch/gesture events.
   RenderWidgetHostViewBase* last_emulated_event_root_view_;

content/browser/renderer_host/render_widget_host_view_child_frame.cc

@@ -528,6 +528,24 @@ void RenderWidgetHostViewChildFrame::GestureEventAck(
       ack_result == INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS ||
       ack_result == INPUT_EVENT_ACK_STATE_CONSUMED_SHOULD_BUBBLE;
 
+// The inertial events on Mac should still get bubbled since there is no GFS to
+// bubble and the inertial events are received from the OS.
+#if !defined(OS_MACOSX)
+  // When a GFS is bubbled, we still send it to the fling controller of the
+  // child view to finish the scroll sequence. However the GSU and GSE events
+  // that are generated by the child view's fling controller do not need to get
+  // bubbled since the GFS event itself is bubbled and the target's fling
+  // controller will take care of flinging.
+  if ((event.GetType() == blink::WebInputEvent::kGestureScrollEnd &&
+       event.data.scroll_end.inertial_phase ==
+           blink::WebGestureEvent::kMomentumPhase) ||
+      (event.GetType() == blink::WebInputEvent::kGestureScrollUpdate &&
+       event.data.scroll_update.inertial_phase ==
+           blink::WebGestureEvent::kMomentumPhase)) {
+    return;
+  }
+#endif  // defined(OS_MACOSX)
+
   if ((event.GetType() == blink::WebInputEvent::kGestureScrollBegin) &&
       should_bubble) {
     DCHECK(!is_scroll_sequence_bubbling_);
@@ -546,7 +564,8 @@ void RenderWidgetHostViewChildFrame::GestureEventAck(
        should_bubble) ||
       event.GetType() == blink::WebInputEvent::kGestureScrollUpdate ||
       event.GetType() == blink::WebInputEvent::kGestureScrollEnd ||
-      event.GetType() == blink::WebInputEvent::kGestureFlingStart) {
+      event.GetType() == blink::WebInputEvent::kGestureFlingStart ||
+      event.GetType() == blink::WebInputEvent::kGestureFlingCancel) {
     frame_connector_->BubbleScrollEvent(event);
   }
 }