[Android] Perform eager gesture recognition on MotionEvents

content/browser/renderer_host/input/gesture_event_packet.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_GESTURE_EVENT_PACKET_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_EVENT_PACKET_H_
+
+#include "content/common/content_export.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+
+namespace content {
+
+// Acts as a transport container for gestures created by a particular event, be
+// that synthetic or otherwise.
+class CONTENT_EXPORT GestureEventPacket {
+ public:
+  enum GestureSource {
+    TOUCH_BEGIN,   // The start of a new gesture sequence.
+    TOUCH,         // Continuation of an existing gesture sequence.
+    TOUCH_TIMEOUT, // Timeout from an existing gesture sequence.
+    SYNTHETIC,     // Non-touch-derived gesture sequence.
+    GESTURE_SOURCE_DEFAULT = TOUCH

[aelias_OOO_until_Jul13, 2014/01/24 05:35:54]

I'd prefer to get rid of this and the default constructor.  If the default
constructor is truly needed for some technical reasons, I'd prefer using an
"INVALID" entry in the enum instead.

[jdduke (slow), 2014/01/24 18:17:35]

Done.

+  };
+
+  GestureEventPacket();
+  explicit GestureEventPacket(GestureSource source);
+  ~GestureEventPacket();
+
+  void Push(const blink::WebGestureEvent& gesture);
+
+  const blink::WebGestureEvent& gesture(size_t i) const { return gestures_[i]; }
+  size_t gesture_count() const { return gesture_count_; }
+  GestureSource gesture_source() const { return gesture_source_; }
+
+  // Utility methods for creating a packet from a particular event.
+  static GestureEventPacket FromTouch(const blink::WebTouchEvent& event);
+  static GestureEventPacket FromGesture(GestureSource source,
+                                        const blink::WebGestureEvent& event);
+
+private:
+  enum { kMaxGesturesPerTouch = 5 };
+  blink::WebGestureEvent gestures_[kMaxGesturesPerTouch];
+  size_t gesture_count_;
+  GestureSource gesture_source_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_EVENT_PACKET_H_