Implement <select> Popup Menu using PagePopup

Source/web/WebPagePopupImpl.cpp

Index: Source/web/WebPagePopupImpl.cpp
diff --git a/Source/web/WebPagePopupImpl.cpp b/Source/web/WebPagePopupImpl.cpp
index 1250ff583a31de73aba6b1fe746d78662811ba95..128b77a045d09a80970865d55b8a407002be5e35 100644
--- a/Source/web/WebPagePopupImpl.cpp
+++ b/Source/web/WebPagePopupImpl.cpp
@@ -48,6 +48,7 @@
 #include "modules/accessibility/AXObjectCacheImpl.h"
 #include "platform/EventDispatchForbiddenScope.h"
 #include "platform/LayoutTestSupport.h"
+#include "platform/ScriptForbiddenScope.h"
 #include "platform/TraceEvent.h"
 #include "platform/heap/Handle.h"
 #include "public/platform/WebCompositeAndReadbackAsyncCallback.h"
@@ -260,9 +261,24 @@ bool WebPagePopupImpl::initializePage()
     RefPtr<SharedBuffer> data = SharedBuffer::create();
     m_popupClient->writeDocument(data.get());
     frame->loader().load(FrameLoadRequest(0, blankURL(), SubstituteData(data, "text/html", "UTF-8", KURL(), ForceSynchronousLoad)));
+
+    m_popupClient->didWriteDocument(frame->document());
+
     return true;
 }
 
+void WebPagePopupImpl::postMessage(const String& message)
+{
+    if (!m_page)
+        return;
+    ScriptForbiddenScope::AllowUserAgentScript allowScript;
+    LocalDOMWindow* window = toLocalFrame(m_page->mainFrame())->localDOMWindow();
+    if (!window)
+        return;
+    RefPtrWillBeRawPtr<MessageEvent> event = MessageEvent::create(message);
+    window->dispatchEvent(event);
+}
+
 void WebPagePopupImpl::destroyPage()
 {
     if (!m_page)