Add test to make sure if PPB_Audio_Shared::StartThread() works.

ppapi/shared_impl/ppb_audio_shared.cc

 // Copyright (c) 2012 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 "ppapi/shared_impl/ppb_audio_shared.h"
 
 #include "base/logging.h"
 #include "ppapi/shared_impl/ppapi_globals.h"
 #include "ppapi/shared_impl/ppb_audio_config_shared.h"
 #include "ppapi/shared_impl/proxy_lock.h"
@@ skipping 128 matching lines @@
   memset(shared_memory_->memory(), 0, shared_memory_size_);
   memset(client_buffer_.get(), 0, client_buffer_size_bytes_);
 #if !defined(OS_NACL)
   DCHECK(!audio_thread_.get());
   audio_thread_.reset(
       new base::DelegateSimpleThread(this, "plugin_audio_thread"));
   audio_thread_->Start();
 #else
   // Use NaCl's special API for IRT code that creates threads that call back
   // into user code.
-  if (NULL == thread_functions.thread_create ||
-      NULL == thread_functions.thread_join)
+  if (!IsThreadFunctionReady())
     return;
 
+  DCHECK(!thread_active_);
   int result = thread_functions.thread_create(&thread_id_, CallRun, this);
   DCHECK_EQ(result, 0);
   thread_active_ = true;
 #endif
 }
 
 void PPB_Audio_Shared::StopThread() {
 #if !defined(OS_NACL)
   if (audio_thread_.get()) {
     // In general, the audio thread should not do Pepper calls, but it might
     // anyway (for example, our Audio test does CallOnMainThread). If it did
     // a pepper call which acquires the lock (most of them do), and we try to
     // shut down the thread and Join it while holding the lock, we would
     // deadlock. So we give up the lock here so that the thread at least _can_
     // make Pepper calls without causing deadlock.
     CallWhileUnlocked(base::Bind(&base::DelegateSimpleThread::Join,
                                  base::Unretained(audio_thread_.get())));
     audio_thread_.reset();
   }
 #else
   if (thread_active_) {
     // See comment above about why we unlock here.
     int result = CallWhileUnlocked(thread_functions.thread_join, thread_id_);
     DCHECK_EQ(0, result);
     thread_active_ = false;
   }
 #endif
 }
 
+// static
+bool PPB_Audio_Shared::IsThreadFunctionReady() {
+#if defined(OS_NACL)
+  if (thread_functions.thread_create == NULL ||
+      thread_functions.thread_join == NULL)
+    return false;
+#endif
+  return true;
+}
+
 #if defined(OS_NACL)
 // static
 void PPB_Audio_Shared::SetThreadFunctions(
     const struct PP_ThreadFunctions* functions) {
-  DCHECK(thread_functions.thread_create == NULL);
-  DCHECK(thread_functions.thread_join == NULL);
   thread_functions = *functions;
 }
 
 // static
 void PPB_Audio_Shared::CallRun(void* self) {
   PPB_Audio_Shared* audio = static_cast<PPB_Audio_Shared*>(self);
   audio->Run();
 }
 #endif
 
@@ skipping 20 matching lines @@
     // Let the other end know which buffer we just filled.  The buffer index is
     // used to ensure the other end is getting the buffer it expects.  For more
     // details on how this works see AudioSyncReader::WaitUntilDataIsReady().
     size_t bytes_sent = socket_->Send(&buffer_index_, sizeof(buffer_index_));
     if (bytes_sent != sizeof(buffer_index_))
       break;
   }
 }
 
 }  // namespace ppapi