Initial browser-side implementation for touch-action

content/browser/renderer_host/input/touch_action_filter.cc

Index: content/browser/renderer_host/input/touch_action_filter.cc
diff --git a/content/browser/renderer_host/input/touch_action_filter.cc b/content/browser/renderer_host/input/touch_action_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e75181d7ccb1d560972e72e95c3f97437b248747
--- /dev/null
+++ b/content/browser/renderer_host/input/touch_action_filter.cc
@@ -0,0 +1,59 @@
+// 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.
+
+#include "content/browser/renderer_host/input/touch_action_filter.h"
+
+#include "third_party/WebKit/public/web/WebInputEvent.h"
+
+using blink::WebInputEvent;
+using blink::WebGestureEvent;
+
+namespace content {
+
+bool TouchActionFilter::FilterGestureEvent(
+    const WebGestureEvent& gesture_event)

[jdduke (slow), 2013/11/20 23:03:02]

Nit: Brace on same line.

[Rick Byers, 2013/11/21 02:37:36]

Done.

+{
+  // Filter for allowable touch actions first (eg. before the TouchEventQueue
+  // can decide to send a touch cancel event).
+  // TODO(rbyers): Add touch-action control over for pinch.  crbug.com/247566.
+  switch(gesture_event.type) {
+    case WebInputEvent::GestureScrollBegin:
+      if (allowed_touch_action_ == TOUCH_ACTION_NONE)
+        drop_scroll_gesture_events_ = true;
+      // FALL THROUGH
+    case WebInputEvent::GestureScrollUpdate:
+    case WebInputEvent::GestureScrollUpdateWithoutPropagation:

[sadrul, 2013/11/20 23:28:30]

I don't believe we actually ever send this event

[Rick Byers, 2013/11/21 02:37:36]

Yeah, looks like it's only ever generated in blink.  Removed.

+      if (drop_scroll_gesture_events_)
+        return true;
+      break;
+
+    case WebInputEvent::GestureScrollEnd:
+    case WebInputEvent::GestureFlingStart:
+      allowed_touch_action_ = content::TOUCH_ACTION_AUTO;
+      if (drop_scroll_gesture_events_) {
+        drop_scroll_gesture_events_ = false;
+        return true;
+      }
+      break;
+
+    default:

[sadrul, 2013/11/20 23:28:30]

NOTREACHED()?

[Rick Byers, 2013/11/21 02:37:36]

Nope - want to return false for all other types of gesture events (Tap, etc.). 
Added comment.

+      break;
+  }
+
+  return false;
+}
+
+void TouchActionFilter::OnSetTouchAction(
+    content::TouchAction touch_action)

[jdduke (slow), 2013/11/20 23:03:02]

Same as above.

[Rick Byers, 2013/11/21 02:37:36]

Done.

+{
+  // For multiple fingers, we take the intersection of the touch actions for
+  // all fingers that have gone down during this action.
+  // TODO(rbyers): What exact multi-finger semantic do we want?  This is left
+  // as implementation-defined in the pointer events specification.
+  // crbug.com/247566.
+  if (touch_action == content::TOUCH_ACTION_NONE)
+    allowed_touch_action_ = content::TOUCH_ACTION_NONE;
+}
+
+}