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

ash/root_window_controller.cc

Index: ash/root_window_controller.cc
diff --git a/ash/root_window_controller.cc b/ash/root_window_controller.cc
index 68bbc74426e0029a37837c1bb102429d1182934d..91acd12e5e39d0c3497b95cc29bf89485b01fd56 100644
--- a/ash/root_window_controller.cc
+++ b/ash/root_window_controller.cc
@@ -676,6 +676,14 @@ bool RootWindowController::IsVirtualKeyboardWindow(aura::Window* window) {
   return parent ? parent->Contains(window) : false;
 }
 
+void RootWindowController::SetTouchAccessibilityAnchorPoint(
+    const gfx::Point& anchor_point) {
+#if defined(OS_CHROMEOS)
+  if (touch_exploration_manager_)
+    touch_exploration_manager_->SetTouchAccessibilityAnchorPoint(anchor_point);
+#endif  // defined(OS_CHROMEOS)
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // RootWindowController, private: