Call willInsertBody() in MediaDocument::createDocumentStructure()

third_party/WebKit/Source/core/html/MediaDocument.cpp

Index: third_party/WebKit/Source/core/html/MediaDocument.cpp
diff --git a/third_party/WebKit/Source/core/html/MediaDocument.cpp b/third_party/WebKit/Source/core/html/MediaDocument.cpp
index cbc672aa46d42f3a6392ca173f22cec233bd6de1..7473bf87668e241779f492600ffb5fd0d2362cb3 100644
--- a/third_party/WebKit/Source/core/html/MediaDocument.cpp
+++ b/third_party/WebKit/Source/core/html/MediaDocument.cpp
@@ -144,6 +144,8 @@ void MediaDocumentParser::createDocumentStructure() {
   HTMLBodyElement* body = HTMLBodyElement::create(*document());
   body->setAttribute(styleAttr, "margin: 0px;");
 
+  document()->willInsertBody();
+
   HTMLDivElement* div = HTMLDivElement::create(*document());
   // Style sheets for media controls are lazily loaded until a media element is
   // encountered.  As a result, elements encountered before the media element