Implement autoplay gesture override experiment.

Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 2461 matching lines @@
                 compositeForSlimmingPaintV2();
             }
 
             if (RuntimeEnabledFeatures::frameTimingSupportEnabled())
                 updateFrameTimingRequestsIfNeeded();
 
             ASSERT(!view->hasPendingSelection());
             ASSERT(lifecycle().state() == DocumentLifecycle::PaintInvalidationClean
                 || (RuntimeEnabledFeatures::slimmingPaintV2Enabled() && lifecycle().state() == DocumentLifecycle::CompositingForSlimmingPaintV2Clean));
         }
+
+        // Temporary callback for crbug.com/487345,402044
+        view->sendMediaPositionChangeNotifications();

[ojan, 2015/09/01 20:20:11]

Please move this to the end of the AllPhases branch right above here.

Also, add:
TODO(ojan): Make this more general to be used by PositionObserver and rAF
throttling.

[liberato (no reviews please), 2015/09/04 06:49:45]

Done.

     }
 
 #ifndef NDEBUG
     // TODO(jchaffraix): We will want to clear the clip rects in release too
     // to reduce our long-term memory consumption. However this requires us
     // to migrate all of the clip rects to the state machine and evaluate
     // the performance impacts of this.
     layoutView()->layer()->clipper().clearClipRectsIncludingDescendants(AbsoluteClipRects);
 #endif
 }
@@ skipping 1479 matching lines @@
 
     if (!graphicsLayer)
         return;
 
     DeprecatedPaintLayer::mapRectToPaintInvalidationBacking(localFrame->contentLayoutObject(), paintInvalidationContainer, viewRect);
 
     graphicsLayerTimingRequests.add(graphicsLayer, Vector<std::pair<int64_t, WebRect>>()).storedValue->value.append(std::make_pair(m_frame->frameID(), enclosingIntRect(viewRect)));
 }
 
 } // namespace blink