PPAPI: Make blocking completion callbacks work.

ppapi/shared_impl/ppb_audio_input_shared.cc

Index: ppapi/shared_impl/ppb_audio_input_shared.cc
diff --git a/ppapi/shared_impl/ppb_audio_input_shared.cc b/ppapi/shared_impl/ppb_audio_input_shared.cc
index 7a7aeef20ccb867e0b68fde85691ee6c5aec7dd3..618014ecd2a89b1219eddb520f1b9995db56283a 100644
--- a/ppapi/shared_impl/ppb_audio_input_shared.cc
+++ b/ppapi/shared_impl/ppb_audio_input_shared.cc
@@ -53,11 +53,8 @@ thunk::PPB_AudioInput_API* PPB_AudioInput_Shared::AsPPB_AudioInput_API() {
   return this;
 }
 
-int32_t PPB_AudioInput_Shared::EnumerateDevices(
-    PP_Resource* devices,
-    const PP_CompletionCallback& callback) {
-  if (!callback.func)
-    return PP_ERROR_BLOCKS_MAIN_THREAD;
+int32_t PPB_AudioInput_Shared::EnumerateDevices(PP_Resource* devices,
+                                                ApiCallbackType callback) {
   if (TrackedCallback::IsPending(enumerate_devices_callback_))
     return PP_ERROR_INPROGRESS;
 
@@ -69,7 +66,7 @@ int32_t PPB_AudioInput_Shared::Open(
     PP_Resource config,
     PPB_AudioInput_Callback audio_input_callback,
     void* user_data,
-    const PP_CompletionCallback& callback) {
+    ApiCallbackType callback) {
   if (!audio_input_callback)
     return PP_ERROR_BADARGUMENT;
 
@@ -173,8 +170,10 @@ void PPB_AudioInput_Shared::OnOpenComplete(
 }
 
 // static
-PP_CompletionCallback PPB_AudioInput_Shared::MakeIgnoredCompletionCallback() {
-  return PP_MakeCompletionCallback(&IgnoredCompletionCallback, NULL);
+ApiCallbackType PPB_AudioInput_Shared::MakeIgnoredCompletionCallback(
+    Resource* resource) {
+  return new TrackedCallback(resource,
+      PP_MakeCompletionCallback(&IgnoredCompletionCallback, NULL));
 }
 
 void PPB_AudioInput_Shared::SetStartCaptureState() {
@@ -250,7 +249,7 @@ int32_t PPB_AudioInput_Shared::CommonOpen(
     PP_Resource config,
     PPB_AudioInput_Callback audio_input_callback,
     void* user_data,
-    PP_CompletionCallback callback) {
+    ApiCallbackType callback) {
   if (open_state_ != BEFORE_OPEN)
     return PP_ERROR_FAILED;
 
@@ -259,9 +258,6 @@ int32_t PPB_AudioInput_Shared::CommonOpen(
   if (enter_config.failed())
     return PP_ERROR_BADARGUMENT;
 
-  if (!callback.func)
-    return PP_ERROR_BLOCKS_MAIN_THREAD;
-
   if (TrackedCallback::IsPending(open_callback_))
     return PP_ERROR_INPROGRESS;