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

content/child/npapi/plugin_string_stream.cc

 // Copyright (c) 2010 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 "content/child/npapi/plugin_string_stream.h"
 
 #include "url/gurl.h"
 
 namespace content {
 
 PluginStringStream::PluginStringStream(
     PluginInstance* instance,
-    const GURL& url,
-    bool notify_needed,
-    void* notify_data)
-    : PluginStream(instance, url.spec().c_str(), notify_needed, notify_data) {
+    const GURL& url)
+    : PluginStream(instance, url.spec().c_str()) {
 }
 
 PluginStringStream::~PluginStringStream() {
 }
 
 void PluginStringStream::SendToPlugin(const std::string &data,
                                       const std::string &mime_type) {
   // Protect the stream against it being destroyed or the whole plugin instance
   // being destroyed within the plugin stream callbacks.
   scoped_refptr<PluginStringStream> protect(this);
 
   int length = static_cast<int>(data.length());
   if (Open(mime_type, std::string(), length, 0, false)) {
     // TODO - check if it was not fully sent, and figure out a backup plan.
     int written = Write(data.c_str(), length, 0);
     NPReason reason = written == length ? NPRES_DONE : NPRES_NETWORK_ERR;
     Close(reason);
   }
 }
 
 }  // namespace content