[Tracking Patch] Unified gesture detection

content/browser/renderer_host/input/content_gesture_provider.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_CONTENT_GESTURE_PROVIDER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_CONTENT_GESTURE_PROVIDER_H_
+
+#include "base/basictypes.h"
+#include "content/browser/renderer_host/input/gesture_event_packet.h"
+#include "content/browser/renderer_host/input/touch_disposition_gesture_filter.h"
+#include "ui/events/gesture_detection/gesture_provider.h"
+
+namespace content {
+
+struct NativeWebTouchEvent;
+
+class ContentGestureProviderClient {
+ public:
+  virtual ~ContentGestureProviderClient() {}
+  virtual void OnGestureEvent(const blink::WebGestureEvent& event) = 0;
+};
+
+// Provides gesture detection and dispatch given a sequence of touch events
+// and touch event acks.
+class ContentGestureProvider : public TouchDispositionGestureFilterClient,
+                               public ui::GestureProviderClient {
+ public:
+  ContentGestureProvider(ContentGestureProviderClient* client,
+                         float touch_to_gesture_scale);
+
+  // Returns true if |event| was both valid and successfully handled by the
+  // gesture detector.  Otherwise, returns false, in which case the caller
+  // should simply drop |event|.
+  bool OnTouchEvent(const NativeWebTouchEvent& event);
+
+  // To be called upon ack of an event that was forwarded after a successful
+  // call to |OnTouchEvent()|.
+  void OnTouchEventAck(InputEventAckState ack_state);
+
+  // Methods delegated to |gesture_provider_|.
+  void ResetGestureDetectors();
+  void CancelActiveTouchSequence();
+  void UpdateMultiTouchSupport(bool support_multi_touch_zoom);
+  void UpdateDoubleTapSupportForPlatform(bool support_double_tap);
+  void UpdateDoubleTapSupportForPage(bool support_double_tap);
+
+ private:
+  // ui::GestureProviderClient
+  virtual void OnGestureEvent(const ui::GestureEventParams& params) OVERRIDE;
+
+  // TouchDispositionGestureFilterClient
+  virtual void ForwardGestureEvent(const blink::WebGestureEvent& event)
+      OVERRIDE;
+
+  ContentGestureProviderClient* const client_;
+  float touch_to_gesture_scale_;
+
+  ui::GestureProvider gesture_provider_;
+  TouchDispositionGestureFilter gesture_filter_;
+
+  bool handling_event_;
+  GestureEventPacket pending_gesture_packet_;
+
+  DISALLOW_COPY_AND_ASSIGN(ContentGestureProvider);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_CONTENT_GESTURE_PROVIDER_H_