Implement autoplay gesture override experiment.

Source/core/layout/LayoutView.cpp

Index: Source/core/layout/LayoutView.cpp
diff --git a/Source/core/layout/LayoutView.cpp b/Source/core/layout/LayoutView.cpp
index 6d382e74a7b20b63b47724a53c4b8287df0b300c..27caf97a450bafb08ee0e4ef2ed2380efea99cef 100644
--- a/Source/core/layout/LayoutView.cpp
+++ b/Source/core/layout/LayoutView.cpp
@@ -28,10 +28,12 @@
 #include "core/frame/Settings.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/HTMLIFrameElement.h"
+#include "core/html/HTMLVideoElement.h"
 #include "core/inspector/InspectorTraceEvents.h"
 #include "core/layout/HitTestResult.h"
 #include "core/layout/LayoutFlowThread.h"
 #include "core/layout/LayoutGeometryMap.h"
+#include "core/layout/LayoutMedia.h"
 #include "core/layout/LayoutPart.h"
 #include "core/layout/LayoutQuote.h"
 #include "core/layout/LayoutScrollbarPart.h"
@@ -1012,4 +1014,27 @@ void LayoutView::willBeDestroyed()
     m_compositor.clear();
 }
 
+void LayoutView::registerMediaForPositionChangeNotification(LayoutMedia* media)
+{
+    if (!m_mediaForPositionNotification.contains(media))
+        m_mediaForPositionNotification.append(media);
+}
+
+void LayoutView::unregisterMediaForPositionChangeNotification(LayoutMedia* media)
+{
+    size_t at = m_mediaForPositionNotification.find(media);
+    if (at != kNotFound)
+        m_mediaForPositionNotification.remove(at);
+}
+
+void LayoutView::sendMediaPositionChangeNotifications()
+{
+    for (LayoutMedia** media = m_mediaForPositionNotification.begin();

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

C++11 auto to make this for loop more readable. See the following as an example:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

[liberato (no reviews please), 2015/09/04 06:49:46]

Done.

+        media != m_mediaForPositionNotification.end(); media++) {
+        if (!(*media))
+            continue;
+        (*media)->notifyPositionMayHaveChanged();
+    }
+}
+
 } // namespace blink