Do not convert mouse wheel gesture events in pepper.

content/renderer/render_widget_fullscreen_pepper.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/renderer/render_widget_fullscreen_pepper.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 47 matching lines @@
   void SendUnlockMouseRequest() override;
 
   RenderWidgetFullscreenPepper* widget_;
 
   DISALLOW_COPY_AND_ASSIGN(FullscreenMouseLockDispatcher);
 };
 
 WebMouseEvent WebMouseEventFromGestureEvent(const WebGestureEvent& gesture) {
   WebMouseEvent mouse;
 
+  // Only convert touch screen gesture events, do not convert
+  // touchpad/mouse wheel gesture events. (crbug.com/620974)
+  if (gesture.sourceDevice != blink::WebGestureDeviceTouchscreen)
+    return mouse;
+
   switch (gesture.type) {
     case WebInputEvent::GestureScrollBegin:
       mouse.type = WebInputEvent::MouseDown;
       break;
-
     case WebInputEvent::GestureScrollUpdate:
       mouse.type = WebInputEvent::MouseMove;
       break;
-
     case WebInputEvent::GestureFlingStart:
-      if (gesture.sourceDevice == blink::WebGestureDeviceTouchscreen) {
-        // A scroll gesture on the touchscreen may end with a GestureScrollEnd
-        // when there is no velocity, or a GestureFlingStart when it has a
-        // velocity. In both cases, it should end the drag that was initiated by
-        // the GestureScrollBegin (and subsequent GestureScrollUpdate) events.
-        mouse.type = WebInputEvent::MouseUp;
-        break;
-      } else {
-        return mouse;
-      }
+      // A scroll gesture on the touchscreen may end with a GestureScrollEnd
+      // when there is no velocity, or a GestureFlingStart when it has a
+      // velocity. In both cases, it should end the drag that was initiated by
+      // the GestureScrollBegin (and subsequent GestureScrollUpdate) events.
+      mouse.type = WebInputEvent::MouseUp;
     case WebInputEvent::GestureScrollEnd:
       mouse.type = WebInputEvent::MouseUp;
       break;
-
     default:
-      break;
+      return mouse;
   }
 
-  if (mouse.type == WebInputEvent::Undefined)
-    return mouse;
-
   mouse.timeStampSeconds = gesture.timeStampSeconds;
   mouse.modifiers = gesture.modifiers | WebInputEvent::LeftButtonDown;
   mouse.button = WebMouseEvent::ButtonLeft;
   mouse.clickCount = (mouse.type == WebInputEvent::MouseDown ||
                       mouse.type == WebInputEvent::MouseUp);
 
   mouse.x = gesture.x;
   mouse.y = gesture.y;
   mouse.windowX = gesture.x;
   mouse.windowY = gesture.y;
@@ skipping 272 matching lines @@
 GURL RenderWidgetFullscreenPepper::GetURLForGraphicsContext3D() {
   return active_url_;
 }
 
 void RenderWidgetFullscreenPepper::OnDeviceScaleFactorChanged() {
   if (compositor_)
     compositor_->setDeviceScaleFactor(device_scale_factor_);
 }
 
 }  // namespace content