[Android] Prevent touch interception for browser-consumed touches

content/browser/renderer_host/render_widget_host_view_android.cc

 // Copyright (c) 2012 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/render_widget_host_view_android.h"
 
 #include <android/bitmap.h>
 
 #include "base/android/build_info.h"
 #include "base/basictypes.h"
@@ skipping 730 matching lines @@
     const gfx::Rect rect) {
   if (content_view_core_)
     content_view_core_->OnSmartClipDataExtracted(text, html, rect);
 }
 
 bool RenderWidgetHostViewAndroid::OnTouchEvent(
     const ui::MotionEvent& event) {
   if (!host_)
     return false;
 
+  // If a browser-based widget consumes the touch event, it's critical that
+  // touch event interception be disabled. This avoids issues with
+  // double-handling for embedder-detected gestures like side swipe.
   if (selection_controller_ &&
-      selection_controller_->WillHandleTouchEvent(event))
+      selection_controller_->WillHandleTouchEvent(event)) {
+    RequestDisallowInterceptTouchEvent();
     return true;
+  }
 
-  if (stylus_text_selector_.OnTouchEvent(event))
+  if (stylus_text_selector_.OnTouchEvent(event)) {
+    RequestDisallowInterceptTouchEvent();
     return true;
+  }
 
   ui::FilteredGestureProvider::TouchHandlingResult result =
       gesture_provider_.OnTouchEvent(event);
   if (!result.succeeded)
     return false;
 
   blink::WebTouchEvent web_event =
       ui::CreateWebTouchEventFromMotionEvent(event, result.did_generate_scroll);
   host_->ForwardTouchEventWithLatencyInfo(web_event, ui::LatencyInfo());
 
   // Send a proactive BeginFrame on the next vsync to reduce latency.
   // This is good enough as long as the first touch event has Begin semantics
   // and the actual scroll happens on the next vsync.
   if (observing_root_window_)
     RequestVSyncUpdate(BEGIN_FRAME);
 
   return true;
 }
 
 bool RenderWidgetHostViewAndroid::OnTouchHandleEvent(
     const ui::MotionEvent& event) {
   return selection_controller_ &&
          selection_controller_->WillHandleTouchEvent(event);
 }
 
 void RenderWidgetHostViewAndroid::ResetGestureDetection() {
   const ui::MotionEvent* current_down_event =
       gesture_provider_.GetCurrentDownEvent();
-  if (current_down_event) {
-    scoped_ptr<ui::MotionEvent> cancel_event = current_down_event->Cancel();
-    OnTouchEvent(*cancel_event);
+  if (!current_down_event) {
+    // A hard reset ensures prevention of any timer-based events that might fire
+    // after a touch sequence has ended.
+    gesture_provider_.ResetDetection();
+    return;
   }
 
-  // A hard reset ensures prevention of any timer-based events.
-  gesture_provider_.ResetDetection();
+  scoped_ptr<ui::MotionEvent> cancel_event = current_down_event->Cancel();
+  if (gesture_provider_.OnTouchEvent(*cancel_event).succeeded) {
+    bool causes_scrolling = false;
+    host_->ForwardTouchEventWithLatencyInfo(
+        ui::CreateWebTouchEventFromMotionEvent(*cancel_event, causes_scrolling),
+        ui::LatencyInfo());
+  }
 }
 
 void RenderWidgetHostViewAndroid::OnDidNavigateMainFrameToNewPage() {
   ResetGestureDetection();
 }
 
 void RenderWidgetHostViewAndroid::SetDoubleTapSupportEnabled(bool enabled) {
   gesture_provider_.SetDoubleTapSupportForPlatformEnabled(enabled);
 }
 
@@ skipping 454 matching lines @@
     const gfx::PointF& base,
     const gfx::PointF& extent) {
   DCHECK(content_view_core_);
   content_view_core_->SelectBetweenCoordinates(base, extent);
 }
 
 void RenderWidgetHostViewAndroid::OnSelectionEvent(
     ui::SelectionEventType event) {
   DCHECK(content_view_core_);
   DCHECK(selection_controller_);
-  // Showing the selection action bar can alter the current View coordinates in
-  // such a way that the current MotionEvent stream is suddenly shifted in
-  // space. Avoid the associated scroll jump by pre-emptively cancelling gesture
-  // detection; scrolling after the selection is activated is unnecessary.
-  if (event == ui::SelectionEventType::SELECTION_SHOWN)
+  // If a selection drag has started, it has taken over the active touch
+  // sequence. Immediately cancel gesture detection and any downstream touch
+  // listeners (e.g., web content) to communicate this transfer.
+  if (event == ui::SELECTION_SHOWN)
     ResetGestureDetection();
   content_view_core_->OnSelectionEvent(
       event, selection_controller_->GetStartPosition(),
       GetSelectionRect(*selection_controller_));
 }
 
 scoped_ptr<ui::TouchHandleDrawable>
 RenderWidgetHostViewAndroid::CreateDrawable() {
   DCHECK(content_view_core_);
   if (!using_browser_compositor_)
@@ skipping 243 matching lines @@
   bool needs_animate = false;
   if (overscroll_controller_) {
     needs_animate |= overscroll_controller_->Animate(
         frame_time, content_view_core_->GetLayer().get());
   }
   if (selection_controller_)
     needs_animate |= selection_controller_->Animate(frame_time);
   return needs_animate;
 }
 
+void RenderWidgetHostViewAndroid::RequestDisallowInterceptTouchEvent() {
+  if (content_view_core_)
+    content_view_core_->RequestDisallowInterceptTouchEvent();
+}
+
 void RenderWidgetHostViewAndroid::EvictDelegatedFrame() {
   if (layer_.get())
     DestroyDelegatedContent();
   frame_evictor_->DiscardedFrame();
 }
 
 bool RenderWidgetHostViewAndroid::HasAcceleratedSurface(
     const gfx::Size& desired_size) {
   NOTREACHED();
   return false;
@@ skipping 472 matching lines @@
   results->orientationAngle = display.RotationAsDegree();
   results->orientationType =
       RenderWidgetHostViewBase::GetOrientationTypeForMobile(display);
   gfx::DeviceDisplayInfo info;
   results->depth = info.GetBitsPerPixel();
   results->depthPerComponent = info.GetBitsPerComponent();
   results->isMonochrome = (results->depthPerComponent == 0);
 }
 
 } // namespace content