Mark touchcancel events as uncancelable

content/common/input/web_touch_event_traits.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_COMMON_INPUT_WEB_TOUCH_EVENT_TRAITS_H_
+#define CONTENT_COMMON_INPUT_WEB_TOUCH_EVENT_TRAITS_H_
+
+#include "base/basictypes.h"
+#include "content/common/input/scoped_web_input_event.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+
+namespace content {
+
+// Utility class for performing operations on and with WebTouchEvents.
+class CONTENT_EXPORT WebTouchEventTraits {
+ public:
+  // Returns whether all touches in the event have the specified state.
+  static bool AllTouchPointsHaveState(const blink::WebTouchEvent& event,
+                                      blink::WebTouchPoint::State state);
+
+  // Returns whether this event represents a transition from no active
+  // touches to some active touches (the start of a new "touch sequence").
+  static bool IsTouchSequenceStart(const blink::WebTouchEvent& event);
+
+  // Sets the type of |event| to |type|, resetting any other type-specific
+  // properties and updating the timestamp.
+  static void ResetType(blink::WebInputEvent::Type type,
+                        double timestamp_sec,
+                        blink::WebTouchEvent* event);
+
+  // Like ResetType but also resets the state of all active touches
+  // to match the event type.  This is particularly useful, for example,
+  // in sending a touchcancel for all active touches.
+  static void ResetTypeAndTouchStates(blink::WebInputEvent::Type type,
+                                      double timestamp_sec,
+                                      blink::WebTouchEvent* event);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_INPUT_WEB_TOUCH_EVENT_TRAITS_H_