Revert of Oilpan: Move MediaStreamSource, MediaStreamComponent and MediaStreamDescriptor

Source/platform/exported/WebMediaStream.cpp

Index: Source/platform/exported/WebMediaStream.cpp
diff --git a/Source/platform/exported/WebMediaStream.cpp b/Source/platform/exported/WebMediaStream.cpp
index 42f7fa33b192c67b309a9b1c02bc0656f455fdc8..7ead4c231ef1bd1044035f8ec08ee482abbcfdee 100644
--- a/Source/platform/exported/WebMediaStream.cpp
+++ b/Source/platform/exported/WebMediaStream.cpp
@@ -52,6 +52,11 @@
 };
 
 } // namespace
+
+WebMediaStream::WebMediaStream(const PassRefPtr<MediaStreamDescriptor>& mediaStreamDescriptor)
+    : m_private(mediaStreamDescriptor)
+{
+}
 
 WebMediaStream::WebMediaStream(MediaStreamDescriptor* mediaStreamDescriptor)
     : m_private(mediaStreamDescriptor)
@@ -111,10 +116,15 @@
     m_private->removeRemoteTrack(track);
 }
 
-WebMediaStream& WebMediaStream::operator=(MediaStreamDescriptor* mediaStreamDescriptor)
+WebMediaStream& WebMediaStream::operator=(const PassRefPtr<MediaStreamDescriptor>& mediaStreamDescriptor)
 {
     m_private = mediaStreamDescriptor;
     return *this;
+}
+
+WebMediaStream::operator PassRefPtr<MediaStreamDescriptor>() const
+{
+    return m_private.get();
 }
 
 WebMediaStream::operator MediaStreamDescriptor*() const