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

content/browser/renderer_host/input/synthetic_gesture_target_android.cc

Index: content/browser/renderer_host/input/synthetic_gesture_target_android.cc
diff --git a/content/browser/renderer_host/input/synthetic_gesture_target_android.cc b/content/browser/renderer_host/input/synthetic_gesture_target_android.cc
index acaee85dd949a65891179f14b98806fb53f7c1c5..8c8c9ed53ea5b2b68c7b92d283652fc78065e118 100644
--- a/content/browser/renderer_host/input/synthetic_gesture_target_android.cc
+++ b/content/browser/renderer_host/input/synthetic_gesture_target_android.cc
@@ -5,6 +5,9 @@
 #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"
 
@@ -80,4 +83,15 @@ bool SyntheticGestureTargetAndroid::SupportsSyntheticGestureSourceType(
   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