Consuming a touch move prevents only the next scroll update.

content/browser/renderer_host/input/touch_disposition_gesture_filter.h

Index: content/browser/renderer_host/input/touch_disposition_gesture_filter.h
diff --git a/content/browser/renderer_host/input/touch_disposition_gesture_filter.h b/content/browser/renderer_host/input/touch_disposition_gesture_filter.h
index f2acc3b47c1b1ab6001cd16fa4f1315264baa3a3..2d854af09af72d1071d0897da8b4671c4fe57149 100644
--- a/content/browser/renderer_host/input/touch_disposition_gesture_filter.h
+++ b/content/browser/renderer_host/input/touch_disposition_gesture_filter.h
@@ -5,14 +5,26 @@
 #ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_DISPOSITION_GESTURE_FILTER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_DISPOSITION_GESTURE_FILTER_H_
 
-#include <deque>
+#include <map>
 #include <queue>
+#include <set>
 
 #include "content/browser/renderer_host/input/gesture_event_packet.h"
 #include "content/common/content_export.h"
 #include "content/port/common/input_event_ack_state.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 
+namespace {
+
+enum RequiredTouches {
+  RT_NONE    = 0,
+  RT_START   = 1 << 0,
+  RT_MOVE    = 1 << 1,
+  RT_CURRENT = 1 << 2,
+};
+
+}  // namespace
+
 namespace content {
 
 // Interface with which the |TouchDispositionGestureFilter| forwards gestures
@@ -50,12 +62,46 @@ class CONTENT_EXPORT TouchDispositionGestureFilter {
   bool IsEmpty() const;
 
  private:
+  struct DispositionHandlingInfo {

[jdduke (slow), 2014/02/13 16:53:06]

It looks to me like all of the DispositionHandlingInfo can be moved into
namespace {} within the .cc file.

[tdresser, 2014/02/13 18:14:09]

Done.

+    // A bitwise-OR of |RequiredTouches|.
+    int required_touches;
+    blink::WebInputEvent::Type antecedent_event_type;
+  };
+
+  DispositionHandlingInfo Info(int required_touches) const {

[jdduke (slow), 2014/02/13 16:53:06]

Let's use constructors for this instead of factory functions.

[tdresser, 2014/02/13 18:14:09]

Done.

+    DispositionHandlingInfo info;
+    info.required_touches = required_touches;
+    return info;
+  }
+
+  DispositionHandlingInfo Info(
+      int required_touches,
+      blink::WebInputEvent::Type antecedent_event_type) const {
+    DispositionHandlingInfo info;
+    info.required_touches = required_touches;
+    info.antecedent_event_type = antecedent_event_type;
+    return info;
+  }
+
   // Utility class for tracking gesture events and dispositions for a single
   // gesture sequence. A single sequence corresponds to all gestures created
   // between the first finger down and the last finger up, including gestures
   // generated by timeouts from a statinoary finger.
   class GestureSequence {
    public:
+    struct GestureHandlingState {
+      GestureHandlingState() {

[jdduke (slow), 2014/02/13 16:53:06]

Nit: Move constructor impl into .cc.

[tdresser, 2014/02/13 18:14:09]

Done.

+        seen_ack = false;
+        start_consumed = false;
+        move_consumed = false;
+        no_consumer = false;
+      }
+      bool seen_ack;
+      bool start_consumed;
+      bool move_consumed;
+      bool no_consumer;
+    };
+
     GestureSequence();
     ~GestureSequence();
 
@@ -63,23 +109,30 @@ class CONTENT_EXPORT TouchDispositionGestureFilter {
     void Pop();
     const GestureEventPacket& Front() const;
     void UpdateState(InputEventAckState ack_state);

[jdduke (slow), 2014/02/13 16:53:06]

Do we still need this method?

[tdresser, 2014/02/13 18:14:09]

Yikes, nope. Good catch.

-    bool IsGesturePrevented() const;
+    void UpdateState(GestureEventPacket::GestureSource gesture_source,
+                     InputEventAckState ack_state);
     bool IsEmpty() const;
+    const GestureHandlingState& state() const { return state_; };
 
    private:
     std::queue<GestureEventPacket> packets_;
-    enum GestureHandlingState {
-      PENDING,                 // The sequence has yet to receive an ack.
-      ALLOWED_UNTIL_PREVENTED, // Gestures in the sequence are allowed until
-                               // a source touch is preventDefault'ed.
-      ALWAYS_ALLOWED,          // All remaining sequence gestures are forwarded.
-      ALWAYS_PREVENTED         // All remaining sequence gestures are dropped.
-    };
     GestureHandlingState state_;
   };
+  bool IsGesturePrevented(blink::WebInputEvent::Type type,
+                          InputEventAckState current,
+                          const GestureSequence::GestureHandlingState& state)
+      const;
+
+  DispositionHandlingInfo GetDispositionHandlingInfo(
+      blink::WebInputEvent::Type type) const;
+
   void UpdateAndDispatchPackets(GestureSequence* sequence,
                                 InputEventAckState ack_result);
-  void SendPacket(const GestureEventPacket& packet);
+
+  void FilterAndSendPacket(const GestureEventPacket& packet,
+                           const GestureSequence& sequence,
+                           InputEventAckState ack_state);
+
   void SendGesture(const blink::WebGestureEvent& gesture);
   void CancelTapIfNecessary();
   void CancelFlingIfNecessary();
@@ -89,6 +142,9 @@ class CONTENT_EXPORT TouchDispositionGestureFilter {
   TouchDispositionGestureFilterClient* client_;
   std::queue<GestureSequence> sequences_;
 
+  std::set<blink::WebInputEvent::Type>
+      last_event_of_type_dropped_;
+
   // Bookkeeping for inserting synthetic Gesture{Tap,Fling}Cancel events
   // when necessary, e.g., GestureTapCancel when scrolling begins, or
   // GestureFlingCancel when a user taps following a GestureFlingStart.