Prepare SyntheticPointerAction to handle touch actions for multiple fingers

content/browser/renderer_host/input/synthetic_gesture.h

 // Copyright 2013 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 CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_GESTURE_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_GESTURE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "content/common/content_export.h"
 #include "content/common/input/synthetic_gesture_params.h"
 
 namespace content {
 
 class SyntheticGestureTarget;
 
 // Base class for synthetic gesture implementations. A synthetic gesture class
-// is responsible for forwaring InputEvents, simulating the gesture, to a
+// is responsible for forwarding InputEvents, simulating the gesture, to a
 // SyntheticGestureTarget.
 //
 // Adding new gesture types involved the following steps:
 //   1) Create a sub-type of SyntheticGesture that implements the gesture.
 //   2) Extend SyntheticGesture::Create with the new class.
 //   3) Add at least one unit test per supported input source type (touch,
 //      mouse, etc) to SyntheticGestureController unit tests. The unit tests
 //      only checks basic functionality and termination. If the gesture is
 //      hooked up to Telemetry its correctness can additionally be tested there.
 class CONTENT_EXPORT SyntheticGesture {
  public:
   SyntheticGesture();
   virtual ~SyntheticGesture();
 
   static std::unique_ptr<SyntheticGesture> Create(
       const SyntheticGestureParams& gesture_params);
 
   enum Result {
     GESTURE_RUNNING,
     GESTURE_FINISHED,
+    // Received when the user input parameters for SyntheticPointerAction are
+    // invalid.
+    POINTER_ACTION_INPUT_INVALID,
     GESTURE_SOURCE_TYPE_NOT_IMPLEMENTED,
     GESTURE_RESULT_MAX = GESTURE_SOURCE_TYPE_NOT_IMPLEMENTED
   };
 
   // Update the state of the gesture and forward the appropriate events to the
   // platform. This function is called repeatedly by the synthetic gesture
   // controller until it stops returning GESTURE_RUNNING.
   virtual Result ForwardInputEvents(
       const base::TimeTicks& timestamp, SyntheticGestureTarget* target) = 0;
 
  protected:
   DISALLOW_COPY_AND_ASSIGN(SyntheticGesture);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_GESTURE_H_