Future proof against things like http://crbug.com/91521

BUG=91521
TEST=Remove ffmpegsumo.so from a mac chrome build and attempt to use it as a client in a chromoting session.
     Check your logs. You should see Media library not initialized. Also, plugin shouldn't crash.

Review URL: http://codereview.chromium.org/7562016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@95414 0039d316-1c4b-4281-b951-d872f2087c98

remoting/client/client_context.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -7,13 +7,15 @@
 #include <string>
 
 #include "base/threading/thread.h"
+#include "remoting/client/plugin/pepper_util.h"
 #include "remoting/jingle_glue/jingle_thread.h"
 
 namespace remoting {
 
 ClientContext::ClientContext()
     : main_thread_("ChromotingClientMainThread"),
-      decode_thread_("ChromotingClientDecodeThread") {
+      decode_thread_("ChromotingClientDecodeThread"),
+      started_(false) {
 }
 
 ClientContext::~ClientContext() {
@@ -21,16 +23,22 @@ ClientContext::~ClientContext() {
 
 void ClientContext::Start() {
   // Start all the threads.
+  DCHECK(CurrentlyOnPluginThread());
   main_thread_.Start();
   decode_thread_.Start();
   jingle_thread_.Start();
+  started_ = true;
 }
 
 void ClientContext::Stop() {
-  // Stop all the threads.
-  jingle_thread_.Stop();
-  decode_thread_.Stop();
-  main_thread_.Stop();
+  DCHECK(CurrentlyOnPluginThread());
+  if (started_) {
+    // Stop all the threads.
+    jingle_thread_.Stop();
+    decode_thread_.Stop();
+    main_thread_.Stop();
+    started_ = false;
+  }
 }
 
 JingleThread* ClientContext::jingle_thread() {

remoting/client/client_context.h

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -13,12 +13,13 @@
 namespace remoting {
 
 // A class that manages threads and running context for the chromoting client
-// process.
+// process. This class is not designed to be subclassed.
 class ClientContext {
  public:
   ClientContext();
-  virtual ~ClientContext();
+  ~ClientContext();
 
+  // Start and Stop must be called from the main plugin thread.
   void Start();
   void Stop();
 
@@ -40,6 +41,9 @@ class ClientContext {
   // A thread that handles all decode operations.
   base::Thread decode_thread_;
 
+  // True if Start() was called on the context.
+  bool started_;
+
   DISALLOW_COPY_AND_ASSIGN(ClientContext);
 };
 

remoting/client/plugin/chromoting_instance.cc

@@ -21,6 +21,7 @@
 // crbug.com/74951
 #include "content/renderer/p2p/ipc_network_manager.h"
 #include "content/renderer/p2p/ipc_socket_factory.h"
+#include "media/base/media.h"
 #include "ppapi/c/dev/ppb_query_policy_dev.h"
 #include "ppapi/cpp/completion_callback.h"
 #include "ppapi/cpp/input_event.h"
@@ -121,7 +122,9 @@ ChromotingInstance::~ChromotingInstance() {
   // before we can call Detach() on |view_proxy_|.
   context_.Stop();
 
-  view_proxy_->Detach();
+  if (view_proxy_.get()) {
+    view_proxy_->Detach();
+  }
 }
 
 bool ChromotingInstance::Init(uint32_t argc,
@@ -132,6 +135,13 @@ bool ChromotingInstance::Init(uint32_t argc,
 
   VLOG(1) << "Started ChromotingInstance::Init";
 
+  // Check to make sure the media library is initialized.
+  // http://crbug.com/91521.
+  if (!media::IsMediaLibraryInitialized()) {
+    logger_.Log(logging::LOG_ERROR, "Media library not initialized.");
+    return false;
+  }
+
   // Start all the threads.
   context_.Start();