Add gesture target fuzzing to views

ui/views/view_constants.h

Index: ui/views/view_constants.h
diff --git a/ui/views/view_constants.h b/ui/views/view_constants.h
index 2b0171f19db780faeb0bd784708f472c08332d37..ab7f84d44c4b87cccd7366d60478563b97f22594 100644
--- a/ui/views/view_constants.h
+++ b/ui/views/view_constants.h
@@ -22,6 +22,13 @@ VIEWS_EXPORT extern const int kAutoscrollRowTimerMS;
 // the item, otherwise it is on the item.
 VIEWS_EXPORT extern const int kDropBetweenPixels;
 
+// A view will only be considered a candidate for touch fuzzing if the touch
+// region covers at least |kFuzzingOverlapPercentage| percent of the area of
+// the view's bounding rectangle. Note that the views tests named
+// GestureEventWithFuzzing and GetEventHandlerForRect may fail if the value
+// of this constant is changed.
+VIEWS_EXPORT extern const float kFuzzingOverlapPercentage;
+
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEW_CONSTANTS_H_