Make touch-based synthetic gesture take touch slop into account.

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 "content/browser/renderer_host/render_widget_host_view_android.h"
+#include "content/common/android/view_configuration.h"
 #include "jni/TouchEventSynthesizer_jni.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 
 using blink::WebTouchEvent;
 
 namespace content {
 
 SyntheticGestureTargetAndroid::SyntheticGestureTargetAndroid(
     RenderWidgetHostImpl* host,
     base::android::ScopedJavaLocalRef<jobject> touch_event_synthesizer)
@@ skipping 55 matching lines @@
 SyntheticGestureParams::GestureSourceType
 SyntheticGestureTargetAndroid::GetDefaultSyntheticGestureSourceType() const {
   return SyntheticGestureParams::TOUCH_INPUT;
 }
 
 bool SyntheticGestureTargetAndroid::SupportsSyntheticGestureSourceType(
     SyntheticGestureParams::GestureSourceType gesture_source_type) const {
   return gesture_source_type == SyntheticGestureParams::TOUCH_INPUT;
 }
 
+int SyntheticGestureTargetAndroid::GetTouchSlopInDips() const {
+  // Option 1: Get touch slop in DIPs directly (deprecated).
+  //return ViewConfiguration::GetTouchSlopInDips();
+
+  // Option 2: Get touch slop in pixels and convert to DIPs
+  RenderWidgetHostViewAndroid* view = static_cast<RenderWidgetHostViewAndroid*>(
+      render_widget_host()->GetView());
+  return
+      ViewConfiguration::GetTouchSlopInPixels() / view->GetDeviceScaleFactor();

[jdduke (slow), 2013/12/02 15:51:40]

You can use the following to save yourself some trouble:

gfx::Screen::GetNativeScreen()->GetPrimaryDisplay().device_scale_factor();

[Dominik Grewe, 2013/12/02 16:18:54]

Nice! Wasn't aware of that.

+}
+
 }  // namespace content