Set the coordinates of the synthetic touch event correctly in SyntheticGestureTargetAura

content/browser/renderer_host/input/synthetic_gesture_target_aura.cc

 // Copyright 2013 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/input/synthetic_gesture_target_aura.h"
 
 #include <stddef.h>
 
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
@@ skipping 16 matching lines @@
   blink::WebScreenInfo screenInfo;
   host->GetWebScreenInfo(&screenInfo);
   device_scale_factor_ = screenInfo.deviceScaleFactor;
 }
 
 void SyntheticGestureTargetAura::DispatchWebTouchEventToPlatform(
     const WebTouchEvent& web_touch,
     const ui::LatencyInfo& latency_info) {
   TouchEventWithLatencyInfo touch_with_latency(web_touch, latency_info);
   for (size_t i = 0; i < touch_with_latency.event.touchesLength; i++) {
-    touch_with_latency.event.touches[i].position.x *= device_scale_factor_;
-    touch_with_latency.event.touches[i].position.y *= device_scale_factor_;
     touch_with_latency.event.touches[i].radiusX *= device_scale_factor_;
     touch_with_latency.event.touches[i].radiusY *= device_scale_factor_;
   }
   ScopedVector<ui::TouchEvent> events;
   bool conversion_success = MakeUITouchEventsFromWebTouchEvents(
       touch_with_latency, &events, LOCAL_COORDINATES);
   DCHECK(conversion_success);
 
   aura::Window* window = GetWindow();
   aura::WindowTreeHost* host = window->GetHost();
   for (ScopedVector<ui::TouchEvent>::iterator iter = events.begin(),
       end = events.end(); iter != end; ++iter) {
     (*iter)->ConvertLocationToTarget(window, host->window());
+
+    // Apply the screen scale factor to the event location after it has been
+    // transformed to the target.
+    gfx::PointF device_location =
+        gfx::ScalePoint((*iter)->location_f(), device_scale_factor_);
+    gfx::PointF device_root_location =
+        gfx::ScalePoint((*iter)->root_location_f(), device_scale_factor_);
+    (*iter)->set_location_f(device_location);
+    (*iter)->set_root_location_f(device_root_location);
     ui::EventDispatchDetails details =
         host->event_processor()->OnEventFromSource(*iter);
     if (details.dispatcher_destroyed)
       break;
   }
 }
 
 void SyntheticGestureTargetAura::DispatchWebMouseWheelEventToPlatform(
       const blink::WebMouseWheelEvent& web_wheel,
       const ui::LatencyInfo&) {
@@ skipping 103 matching lines @@
       ->min_distance_for_pinch_scroll_in_pixels();
 }
 
 aura::Window* SyntheticGestureTargetAura::GetWindow() const {
   aura::Window* window = render_widget_host()->GetView()->GetNativeView();
   DCHECK(window);
   return window;
 }
 
 }  // namespace content