Initial browser-side implementation for touch-action

content/browser/renderer_host/input/touch_action_filter.h

Index: content/browser/renderer_host/input/touch_action_filter.h
diff --git a/content/browser/renderer_host/input/touch_action_filter.h b/content/browser/renderer_host/input/touch_action_filter.h
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+++ b/content/browser/renderer_host/input/touch_action_filter.h
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+// 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_TOUCH_ACTION_FILTER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_ACTION_FILTER_H_
+
+#include "base/basictypes.h"
+#include "content/common/content_export.h"
+#include "content/public/common/touch_action.h"
+
+namespace blink {
+class WebGestureEvent;
+}
+
+namespace content {
+
+// The TouchActionFilter is responsible for filtering scroll and pinch gesture
+// events according to the CSS touch-action values the renderer has sent for
+// each touch point.
+// For details see the touch-action design doc at http://goo.gl/KcKbxQ.
+class CONTENT_EXPORT TouchActionFilter {
+public:
+  TouchActionFilter() :
+    drop_scroll_gesture_events_(false),
+    allowed_touch_action_(TOUCH_ACTION_AUTO)
+  {
+  }
+
+  // Returns true if the supplied gesture event should be dropped based on
+  // the current touch-action state.
+  bool FilterGestureEvent(const blink::WebGestureEvent& gesture_event);
+
+  // Called when a set-touch-action message is received from the renderer
+  // for a touch start event that is currently in flight.
+  void OnSetTouchAction(int touch_id, content::TouchAction touchAction);
+
+private:
+  // Whether GestureScroll events should be discarded due to touch-action.
+  bool drop_scroll_gesture_events_;
+
+  // What touch actions are currently permitted.
+  content::TouchAction allowed_touch_action_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchActionFilter);
+};
+
+}
+#endif // CONTENT_BROWSER_RENDERER_HOST_INPUT_TOUCH_ACTION_FILTER_H_