Prepare SyntheticPointerAction to handle touch actions for multiple fingers

content/browser/renderer_host/input/synthetic_pointer_action_controller.h

+// Copyright 2016 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_CONTROLLER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_POINTER_ACTION_CONTROLLER_H_
+
+#include "content/browser/renderer_host/input/synthetic_pointer.h"
+#include "content/browser/renderer_host/input/synthetic_pointer_action.h"
+#include "content/common/content_export.h"
+#include "content/common/input/synthetic_pointer_action_params.h"
+
+namespace content {
+
+class CONTENT_EXPORT SyntheticPointerActionController {
+ public:
+  SyntheticPointerActionController();
+  ~SyntheticPointerActionController();
+
+  std::unique_ptr<SyntheticGesture> CreateSyntheticPointerAction(
+      const SyntheticPointerActionParams& gesture_params);
+
+  void ResetSyntheticPointer();
+
+  void SetDefaultGestureSourceType(
+      SyntheticGestureParams::GestureSourceType default_type);
+
+ private:
+  friend class MockSyntheticGestureController;
+
+  void SetSyntheticPointer(const SyntheticPointerActionParams& gesture_params);
+  // Only for tests in SyntheticGestureControllerTest.
+  int PointerIndex(int index) const;
+  // A list keeps all the action paramters, which should be executed in the

[tdresser, 2016/05/19 17:57:04]

paramters -> parameters

"A list of all"

[lanwei, 2016/05/20 01:48:16]

Done.

+  // same frame.
+  std::vector<SyntheticPointerActionParams> action_param_list_;
+  // For one pointer action sequence, we should use the same SyntheticPointer
+  // object, and keep the states for all touch points.
+  std::unique_ptr<SyntheticPointer> synthetic_pointer_;
+  // This is used to map the indexes of touch points between the ones that
+  // users define and the real indexes kept in the touch event.

[tdresser, 2016/05/19 17:57:04]

"users define." Let's be more specific about which indexes are being referred to
here. Where do the "user defined" indexes come from? 

+  SyntheticPointerAction::IndexMap index_map_;
+
+  SyntheticGestureParams::GestureSourceType default_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(SyntheticPointerActionController);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_SYNTHETIC_POINTER_ACTION_CONTROLLER_H_