Oilpan: prevent player from accessing its media element during finalization

Source/web/WebMediaPlayerClientImpl.cpp

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "web/WebMediaPlayerClientImpl.h"
 
 #include "core/frame/LocalFrame.h"
 #include "core/html/HTMLMediaElement.h"
 #include "core/html/TimeRanges.h"
@@ skipping 55 matching lines @@
     return m_webMediaPlayer.get();
 }
 
 // WebMediaPlayerClient --------------------------------------------------------
 
 WebMediaPlayerClientImpl::~WebMediaPlayerClientImpl()
 {
     // Explicitly destroy the WebMediaPlayer to allow verification of tear down.
     m_webMediaPlayer.clear();
 
-    HTMLMediaElementEncryptedMedia::playerDestroyed(mediaElement());
+    if (m_client)
+        HTMLMediaElementEncryptedMedia::playerDestroyed(mediaElement());
+}
+
+void WebMediaPlayerClientImpl::detach()
+{
+    m_client = 0;
 }
 
 void WebMediaPlayerClientImpl::networkStateChanged()
 {
     m_client->mediaPlayerNetworkStateChanged();
 }
 
 void WebMediaPlayerClientImpl::readyStateChanged()
 {
     m_client->mediaPlayerReadyStateChanged();
@@ skipping 49 matching lines @@
     HTMLMediaElementEncryptedMedia::keyMessage(mediaElement(), keySystem, sessionId, message, messageLength, defaultURL);
 }
 
 void WebMediaPlayerClientImpl::keyNeeded(const WebString& contentType, const unsigned char* initData, unsigned initDataLength)
 {
     HTMLMediaElementEncryptedMedia::keyNeeded(mediaElement(), contentType, initData, initDataLength);
 }
 
 void WebMediaPlayerClientImpl::setWebLayer(blink::WebLayer* layer)
 {
-    m_client->mediaPlayerSetWebLayer(layer);
+    ASSERT(m_client || !layer);

[haraken, 2014/05/27 23:09:09]

Nit: I wonder why you need this ASSERT.

[sof, 2014/05/28 05:28:18]

To check that the embedder only tries to clear the layer when in a detached
state. Which the WebMediaPlayer does when it is torn down in the destructor
above.

Exposing a detached state on this client object isn't quite as
contained&restricted as I would have hoped for. Been going back&forth on this
overnight, and I think I prefer the first approach.

+    if (m_client)
+        m_client->mediaPlayerSetWebLayer(layer);
 }
 
 void WebMediaPlayerClientImpl::addTextTrack(WebInbandTextTrack* textTrack)
 {
     m_client->mediaPlayerDidAddTextTrack(textTrack);
 }
 
 void WebMediaPlayerClientImpl::removeTextTrack(WebInbandTextTrack* textTrack)
 {
     m_client->mediaPlayerDidRemoveTextTrack(textTrack);
@@ skipping 334 matching lines @@
 
 void WebMediaPlayerClientImpl::AudioClientImpl::setFormat(size_t numberOfChannels, float sampleRate)
 {
     if (m_client)
         m_client->setFormat(numberOfChannels, sampleRate);
 }
 
 #endif
 
 } // namespace blink