[CRD iOS] Ignore touch event when the touch point is out of the canvas in direct input mode

remoting/client/ui/input_strategy.h

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_CLIENT_UI_INPUT_STRATEGY_H_
 #define REMOTING_CLIENT_UI_INPUT_STRATEGY_H_
 
 #include "remoting/client/ui/view_matrix.h"
 
 namespace remoting {
@@ skipping 29 matching lines @@
   // change.
   // simultaneous_gesture: Gesture that is simultaneously in progress.
   // Returns true if this changes the cursor position.
   virtual bool HandlePan(const ViewMatrix::Vector2D& translation,
                          Gesture simultaneous_gesture,
                          DesktopViewport* viewport) = 0;
 
   // Called when a touch input (which will end up injecting a mouse event at
   // certain position in the host) is done at |touch_point|.
   // The implementation should move the cursor to proper position.
-  virtual void TrackTouchInput(const ViewMatrix::Point& touch_point,
+  //
+  // Returns true if |touch_point| is a valid input, false otherwise. If the
+  // input is not valid, the implementation should not change its cursor
+  // position.
+  virtual bool TrackTouchInput(const ViewMatrix::Point& touch_point,
                                const DesktopViewport& viewport) = 0;
 
   // Returns the current cursor position.
   virtual ViewMatrix::Point GetCursorPosition() const = 0;
 
   // Maps a vector (or movement) in the surface coordinate to the vector to be
   // used on the desktop. For example it can be used to map a scroll gesture
   // on the screen to change in mouse wheel position.
   virtual ViewMatrix::Vector2D MapScreenVectorToDesktop(
       const ViewMatrix::Vector2D& delta,
       const DesktopViewport& viewport) const = 0;
 
   // Returns the maximum radius of the feedback animation on the surface's
   // coordinate for the given input type. The feedback will then be shown on the
   // cursor positions returned by GetCursorPosition(). Return 0 if no feedback
   // should be shown.
   virtual float GetFeedbackRadius(InputFeedbackType type) const = 0;
 
   // Returns true if the input strategy maintains a visible cursor on the
   // desktop.
   virtual bool IsCursorVisible() const = 0;
 };
 
 }  // namespace remoting
 #endif  // REMOTING_CLIENT_UI_INPUT_STRATEGY_H_