Consuming a touch move prevents only the next scroll update.

content/browser/renderer_host/input/gesture_event_packet.h

 // Copyright 2014 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 (directly or indirectly)
 // by a touch event.
 class CONTENT_EXPORT GestureEventPacket {
  public:
   enum GestureSource {
-    INVALID = -1,  // Used only for a default-constructed packet..
-    TOUCH_BEGIN,   // The start of a new gesture sequence.
-    TOUCH,         // Continuation of an existing gesture sequence.
-    TOUCH_TIMEOUT, // Timeout from an existing gesture sequence.
+    INVALID = -1,      // Used only for a default-constructed packet.
+    TOUCH_SEQUENCE_BEGIN,       // The start of a new gesture sequence.
+    TOUCH_BEGIN, // A non-primary pointer was put down. TODO - reword these.
+    TOUCH_MOVE,        // A touch point moved.
+    TOUCH_END,   // A touch point lifted.

[jdduke (slow), 2014/02/11 16:02:25]

Now that we're adding a few types, do you think it's worth having a
TOUCH_SEQUENCE_END that would pop a sequence as soon as it's ack'ed?  Rather
than just waiting until we get the ack of a TOUCH_SEQUENCE_BEGIN?   

Also, are we taking into consideration that a TouchCancel cannot be
preventDefault'ed? Looking at the code, I think this gets handled properly
(e.g., GestureScrollEnd/GestureTapCancel on a TouchCancel), but we should
probably add some test for this.

[tdresser, 2014/02/11 21:04:32]

Done.

+    TOUCH_TIMEOUT,     // Timeout from an existing gesture sequence.
   };
 
   GestureEventPacket();
   ~GestureEventPacket();
 
   // Factory methods for creating a packet from a particular event.
   static GestureEventPacket FromTouch(const blink::WebTouchEvent& event);
   static GestureEventPacket FromTouchTimeout(
       const blink::WebGestureEvent& event);
 
   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_; }
 
 private:
   explicit GestureEventPacket(GestureSource source);
 
   enum { kMaxGesturesPerTouch = 5 };
   blink::WebGestureEvent gestures_[kMaxGesturesPerTouch];
   size_t gesture_count_;
   GestureSource gesture_source_;
+  bool is_independent_;

[jdduke (slow), 2014/02/11 16:02:25]

Do we still need this flag?

[tdresser, 2014/02/11 21:04:33]

Nope, removed.

 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_INPUT_GESTURE_EVENT_PACKET_H_