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

content/browser/renderer_host/input/synthetic_gesture_target_base.cc

Index: content/browser/renderer_host/input/synthetic_gesture_target_base.cc
diff --git a/content/browser/renderer_host/input/synthetic_gesture_target_base.cc b/content/browser/renderer_host/input/synthetic_gesture_target_base.cc
index bc6dc8f2f4b373d5d9863ec8e4d8d0bf47ec0998..ef12a078cd78d0843366ac74e433fa667936b24e 100644
--- a/content/browser/renderer_host/input/synthetic_gesture_target_base.cc
+++ b/content/browser/renderer_host/input/synthetic_gesture_target_base.cc
@@ -25,6 +25,13 @@ namespace {
 // fling on Android.
 const int kPointerAssumedStoppedTimeMs = 50;
 
+// SyntheticGestureTargetBase passes input events straight on to the renderer
+// without going through a gesture recognition framework. There is thus no touch
+// slop.
+// On platforms where input events are processed by a gesture recognizer
+// GetTouchSlopInDips() should be overwritten.
+const int kTouchSlopInDips = 0;
+
 }  // namespace
 
 SyntheticGestureTargetBase::SyntheticGestureTargetBase(
@@ -110,4 +117,8 @@ base::TimeDelta SyntheticGestureTargetBase::PointerAssumedStoppedTime()
   return base::TimeDelta::FromMilliseconds(kPointerAssumedStoppedTimeMs);
 }
 
+int SyntheticGestureTargetBase::GetTouchSlopInDips() const {
+  return kTouchSlopInDips;
+}
+
 }  // namespace content