Synthetic pinch gesture take scale factor as parameter.

content/browser/renderer_host/input/synthetic_gesture_target_android.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_android.h"
 
 #include "content/browser/android/content_view_core_impl.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "jni/TouchEventSynthesizer_jni.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
@@ skipping 74 matching lines @@
 void SyntheticGestureTargetAndroid::DispatchWebMouseEventToPlatform(
     const blink::WebMouseEvent& web_mouse, const ui::LatencyInfo&) {
   CHECK(false);
 }
 
 SyntheticGestureParams::GestureSourceType
 SyntheticGestureTargetAndroid::GetDefaultSyntheticGestureSourceType() const {
   return SyntheticGestureParams::TOUCH_INPUT;
 }
 
-int SyntheticGestureTargetAndroid::GetTouchSlopInDips() const {
+float SyntheticGestureTargetAndroid::GetTouchSlopInDips() const {
   float device_scale_factor =
       gfx::Screen::GetNativeScreen()->GetPrimaryDisplay().device_scale_factor();
   return gfx::ViewConfiguration::GetTouchSlopInPixels() / device_scale_factor;
 }
 
+float SyntheticGestureTargetAndroid::GetMinScalingSpanInDips() const {
+  float device_scale_factor =
+      gfx::Screen::GetNativeScreen()->GetPrimaryDisplay().device_scale_factor();
+  return
+      gfx::ViewConfiguration::GetMinScalingSpanInPixels() / device_scale_factor;
+}
+
 }  // namespace content