Fix the double-tap to click gesture in touch accessibility mode.

ash/ash_touch_exploration_manager_chromeos.h

Index: ash/ash_touch_exploration_manager_chromeos.h
diff --git a/ash/ash_touch_exploration_manager_chromeos.h b/ash/ash_touch_exploration_manager_chromeos.h
index e81e1102442441d48e559e7b3fc0d1fa468640e6..be76f5236cd242c1897101b8336dcc335ce1e32b 100644
--- a/ash/ash_touch_exploration_manager_chromeos.h
+++ b/ash/ash_touch_exploration_manager_chromeos.h
@@ -52,6 +52,10 @@ class ASH_EXPORT AshTouchExplorationManager
       aura::Window* gained_active,
       aura::Window* lost_active) override;
 
+  // Update the touch exploration controller so that synthesized touch
+  // events are anchored at this point.
+  void SetTouchAccessibilityAnchorPoint(const gfx::Point& anchor_point);
+
  private:
   void UpdateTouchExplorationState();
   bool VolumeAdjustSoundEnabled();