Prepare SyntheticPointerAction to handle touch actions for multiple fingers

content/browser/renderer_host/input/synthetic_pointer_action.h

 // Copyright 2015 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_POINTER_ACTION_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_POINTER_ACTION_H_
 
+#include <array>
 #include "base/macros.h"
 #include "content/browser/renderer_host/input/synthetic_gesture.h"
 #include "content/browser/renderer_host/input/synthetic_gesture_target.h"
 #include "content/browser/renderer_host/input/synthetic_pointer.h"
 #include "content/common/content_export.h"
 #include "content/common/input/synthetic_pointer_action_params.h"
 
+using blink::WebTouchEvent;
+
 namespace content {
 
 class CONTENT_EXPORT SyntheticPointerAction : public SyntheticGesture {
  public:
+  using IndexMap = std::array<int, WebTouchEvent::touchesLengthCap>;
+
   explicit SyntheticPointerAction(const SyntheticPointerActionParams& params);
-  SyntheticPointerAction(const SyntheticPointerActionParams& params,
-                         SyntheticPointer* synthetic_pointer);
+  SyntheticPointerAction(
+      std::unique_ptr<std::vector<SyntheticPointerActionParams>> param_list,
+      SyntheticPointer* synthetic_pointer,
+      IndexMap* index_map);
   ~SyntheticPointerAction() override;
 
   SyntheticGesture::Result ForwardInputEvents(
       const base::TimeTicks& timestamp,
       SyntheticGestureTarget* target) override;
 
-  void ForwardTouchOrMouseInputEvents(const base::TimeTicks& timestamp,
-                                      SyntheticGestureTarget* target);
+ private:
+  SyntheticGesture::Result ForwardTouchOrMouseInputEvents(
+      const base::TimeTicks& timestamp,
+      SyntheticGestureTarget* target);
+  int GetPointIndex(int index) const { return (*index_map_)[index]; }
+  void SetPointIndex(int index, int point_index) {
+    (*index_map_)[index] = point_index;
+  }
+  bool UserInputCheck(const SyntheticPointerActionParams& params);

[tdresser, 2016/06/28 15:44:11]

Let's add a comment here explaining what UserInputCheck does. Do we eventually
want to determine an error string here too? If so, we might want a TODO for that
here.

[lanwei, 2016/07/07 19:35:31]

Maybe not, this function will just return true or false, but
SyntheticGesture::Result will have more details. 

 
- private:
+  // SyntheticGestureController is responsible to create the
+  // SyntheticPointerActions and control when to forward them.
+  // This will be passed from SyntheticGestureController, which will reset its
+  // value to push a new batch of action parameters.
+  // This contains a list of pointer actions which will be dispatched together.
+  const std::unique_ptr<std::vector<SyntheticPointerActionParams>> param_list_;
+  // These two objects will be owned by SyntheticGestureController, which
+  // will manage their lifetime by initiating them when it starts processing a
+  // pointer action sequence and resetting them when it finishes.
+  SyntheticPointer* synthetic_pointer_;
+  IndexMap* index_map_;
+
   SyntheticPointerActionParams params_;
-  SyntheticPointer* synthetic_pointer_;
 
   DISALLOW_COPY_AND_ASSIGN(SyntheticPointerAction);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_POINTER_ACTION_H_