[Android] Disable fling cancel filtering in the GestureEventQueue

content/browser/android/content_view_core_impl.cc

 // Copyright 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/android/content_view_core_impl.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ skipping 538 matching lines @@
       break;
     default:
       break;
   }
 }
 
 bool ContentViewCoreImpl::FilterInputEvent(const blink::WebInputEvent& event) {
   if (event.type != WebInputEvent::GestureTap &&
       event.type != WebInputEvent::GestureDoubleTap &&
       event.type != WebInputEvent::GestureLongTap &&
-      event.type != WebInputEvent::GestureLongPress)
+      event.type != WebInputEvent::GestureLongPress &&
+      event.type != WebInputEvent::GestureFlingCancel)
     return false;
 
   JNIEnv* env = AttachCurrentThread();
   ScopedJavaLocalRef<jobject> j_obj = java_ref_.get(env);
   if (j_obj.is_null())
     return false;
 
+  if (event.type == WebInputEvent::GestureFlingCancel) {
+    // If no fling is active, either in the compositor or externally-driven,
+    // there's no need to explicitly cancel the fling.
+    bool may_need_fling_cancel =
+        Java_ContentViewCore_isScrollInProgress(env, j_obj.obj());
+    return !may_need_fling_cancel;
+  }
+
   const blink::WebGestureEvent& gesture =
       static_cast<const blink::WebGestureEvent&>(event);
   int gesture_type = ToGestureEventType(event.type);
   return Java_ContentViewCore_filterTapOrPressEvent(env,
                                                     j_obj.obj(),
                                                     gesture_type,
                                                     gesture.x * dpi_scale(),
                                                     gesture.y * dpi_scale());
 
   // TODO(jdduke): Also report double-tap UMA, crbug/347568.
@@ skipping 811 matching lines @@
     return NULL;
 
   return view->GetJavaObject().Release();
 }
 
 bool RegisterContentViewCore(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace content