ViewRoot class for event forwarding on Android

ui/android/view_client.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 UI_ANDROID_VIEW_CLIENT_H_
+#define UI_ANDROID_VIEW_CLIENT_H_
+
+#include <jni.h>
+
+#include "ui/android/ui_android_export.h"
+
+namespace ui {
+
+// Container of motion event data. Used when traversing views along their
+// hierarchy. Actual motion event object will be constructed right before
+// it is used in the |ViewClient| implementation to avoid creating multiple
+// |MotionEventAndroid| instances.
+struct MotionEventData {
+  MotionEventData(float dip_scale,
+                  jobject jevent,
+                  long time,
+                  int action,
+                  int pointer_count,
+                  int history_size,
+                  int action_index,
+                  float pos_x0,
+                  float pos_y0,
+                  float pos_x1,
+                  float pos_y1,
+                  int pointer_id_0,
+                  int pointer_id_1,
+                  float touch_major_0,
+                  float touch_major_1,
+                  float touch_minor_0,
+                  float touch_minor_1,
+                  float orientation_0,
+                  float orientation_1,
+                  float tilt_0,
+                  float tilt_1,
+                  float raw_pos_x,
+                  float raw_pos_y,
+                  int tool_type_0,
+                  int tool_type_1,
+                  int button_state,
+                  int meta_state,
+                  bool is_touch_handle_event);
+
+  MotionEventData(const MotionEventData& other);
+
+  // Returns a new |MotionEventData| object whose position is offset
+  // by a given delta.
+  MotionEventData Offset(float delta_x, float delta_y) const;
+
+  float GetX() const { return pos_x0_ / dip_scale_; }
+  float GetY() const { return pos_y0_ / dip_scale_; }
+
+  const float dip_scale_;
+  const jobject jevent_;
+  const long time_; // ms
+  const int action_;
+  const int pointer_count_;
+  const int history_size_;
+  const int action_index_;
+
+  const float pos_x0_;  // in pixel unit
+  const float pos_y0_;
+  const float pos_x1_;
+  const float pos_y1_;
+
+  const int pointer_id_0_;
+  const int pointer_id_1_;
+  const float touch_major_0_;
+  const float touch_major_1_;
+  const float touch_minor_0_;
+  const float touch_minor_1_;
+  const float orientation_0_;
+  const float orientation_1_;
+  const float tilt_0_;
+  const float tilt_1_;
+  const float raw_pos_x_;
+  const float raw_pos_y_;
+  const int tool_type_0_;
+  const int tool_type_1_;
+  const int button_state_;
+  const int meta_state_;
+  const bool is_touch_handle_event_;
+};
+
+// Client interface used to forward events from Java to native views.
+// Calls are dispatched to its children along the hierarchy of ViewAndroid.
+// Use bool return type to stop propagating the call i.e. overriden method
+// should return true to indicate that the event was handled and stop
+// the processing.
+// Note: Not in use yet. Will be hooked up together with ViewRoot.
+//       See https://crbug.com/671401.
+class UI_ANDROID_EXPORT ViewClient {
+ public:
+  virtual bool OnTouchEvent(const MotionEventData& event);
+};
+
+}  // namespace ui
+
+#endif  // UI_ANDROID_VIEW_CLIENT_H_