Fix the crash for the AudioShared.

ppapi/shared_impl/ppb_audio_shared.cc

Index: ppapi/shared_impl/ppb_audio_shared.cc
diff --git a/ppapi/shared_impl/ppb_audio_shared.cc b/ppapi/shared_impl/ppb_audio_shared.cc
index ced11466970c6e2ba26eb9d87fb3f1c94d49993b..b448011974cf9bbc9930ee48aa2f4b98b07f9223 100644
--- a/ppapi/shared_impl/ppb_audio_shared.cc
+++ b/ppapi/shared_impl/ppb_audio_shared.cc
@@ -5,18 +5,18 @@
 #include "ppapi/shared_impl/ppb_audio_shared.h"
 
 #include "base/logging.h"
+#include "ppapi/nacl_irt/irt_ppapi.h"
 #include "ppapi/shared_impl/ppapi_globals.h"
 #include "ppapi/shared_impl/ppb_audio_config_shared.h"
 #include "ppapi/shared_impl/proxy_lock.h"
 
 namespace ppapi {
 
-#if defined(OS_NACL)
 namespace {
+bool thread_functions_set = false;
 // Because this is static, the function pointers will be NULL initially.
 PP_ThreadFunctions thread_functions;
 }
-#endif  // defined(OS_NACL)
 
 AudioCallbackCombined::AudioCallbackCombined()
     : callback_1_0_(NULL), callback_(NULL) {}
@@ -50,10 +50,8 @@ void AudioCallbackCombined::Run(void* sample_buffer,
 PPB_Audio_Shared::PPB_Audio_Shared()
     : playing_(false),
       shared_memory_size_(0),
-#if defined(OS_NACL)
       thread_id_(0),
       thread_active_(false),
-#endif
       user_data_(NULL),
       client_buffer_size_bytes_(0),
       bytes_per_second_(0),
@@ -77,9 +75,8 @@ void PPB_Audio_Shared::SetStartPlaybackState() {
   DCHECK(!playing_);
 #if !defined(OS_NACL)
   DCHECK(!audio_thread_.get());
-#else
-  DCHECK(!thread_active_);
 #endif
+  DCHECK(!thread_active_);
   // If the socket doesn't exist, that means that the plugin has started before
   // the browser has had a chance to create all the shared memory info and
   // notify us. This is a common case. In this case, we just set the playing_
@@ -138,21 +135,25 @@ void PPB_Audio_Shared::StartThread() {
   // start up quickly enough.
   memset(shared_memory_->memory(), 0, shared_memory_size_);
   memset(client_buffer_.get(), 0, client_buffer_size_bytes_);
+
+  if (thread_functions_set) {

[Mark Seaborn, 2014/03/20 23:23:30]

PPB_Audio is meant to fail under NaCl (for both SFI and non-SFI modes) if user
code didn't call ppapi_register_thread_creator().  Currently the code you have
here won't fail in this case because it falls back to the trusted plugin code
path (for --register-pepper-plugins).

I think you need a runtime flag for this file to indicate whether the plugin is
a nexe or a trusted plugin.

[hidehiko, 2014/04/21 14:47:40]

Done.

+    // 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)
+      return;
+
+    int result = thread_functions.thread_create(&thread_id_, CallRun, this);
+    DCHECK_EQ(result, 0);
+    thread_active_ = true;
+    return;
+  }
+
 #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)
-    return;
-
-  int result = thread_functions.thread_create(&thread_id_, CallRun, this);
-  DCHECK_EQ(result, 0);
-  thread_active_ = true;
 #endif
 }
 
@@ -169,22 +170,22 @@ void PPB_Audio_Shared::StopThread() {
                                  base::Unretained(audio_thread_.get())));
     audio_thread_.reset();
   }
-#else
+#endif
   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
 }
 
-#if defined(OS_NACL)
 // static
 void PPB_Audio_Shared::SetThreadFunctions(
     const struct PP_ThreadFunctions* functions) {
+  DCHECK(!thread_functions_set);
   DCHECK(thread_functions.thread_create == NULL);
   DCHECK(thread_functions.thread_join == NULL);
+  thread_functions_set = true;
   thread_functions = *functions;
 }
 
@@ -193,7 +194,6 @@ void PPB_Audio_Shared::CallRun(void* self) {
   PPB_Audio_Shared* audio = static_cast<PPB_Audio_Shared*>(self);
   audio->Run();
 }
-#endif
 
 void PPB_Audio_Shared::Run() {
   int pending_data = 0;