Remove PluginLoadObserver and related logic, it was only used for NPAPI.

third_party/WebKit/Source/core/loader/FrameLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) Research In Motion Limited 2009. All rights reserved.
  * Copyright (C) 2011 Kris Jordan <krisjordan@gmail.com>
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ skipping 978 matching lines @@
     if (m_documentLoader)
         m_documentLoader->stopLoading();
     m_frame->document()->cancelParsing();
 
     detachDocumentLoader(m_provisionalDocumentLoader);
 
     m_checkTimer.stop();
     m_frame->navigationScheduler().cancel();
 
     m_inStopAllLoaders = false;
-
-    // LocalFrame::detach() can be called multiple times which
-    // means we may no longer have a FrameLoaderClient to talk to.
-    if (client())
-        client()->didStopAllLoaders();
 }
 
 void FrameLoader::didAccessInitialDocument()
 {
     // We only need to notify the client once, and only for the main frame.
     if (isLoadingMainFrame() && !m_didAccessInitialDocument) {
         m_didAccessInitialDocument = true;
         // Notify asynchronously, since this is called within a JavaScript security check.
         m_didAccessInitialDocumentTimer.startOneShot(0, BLINK_FROM_HERE);
     }
@@ skipping 542 matching lines @@
     // FIXME: We need a way to propagate insecure requests policy flags to
     // out-of-process frames. For now, we'll always use default behavior.
     if (!parentFrame->isLocalFrame())
         return nullptr;
 
     ASSERT(toLocalFrame(parentFrame)->document());
     return toLocalFrame(parentFrame)->document()->insecureNavigationsToUpgrade();
 }
 
 } // namespace blink