--- a/dom/plugins/ipc/PPluginModule.ipdl
+++ b/dom/plugins/ipc/PPluginModule.ipdl
@@ -94,18 +94,16 @@ child:
 
   async SettingChanged(PluginSettings settings);
 
   async NPP_SetValue_NPNVaudioDeviceChangeDetails(NPAudioDeviceChangeDetailsIPC changeDetails);
 
   async InitPluginModuleChild(Endpoint<PPluginModuleChild> endpoint);
 
 parent:
-  async NP_InitializeResult(NPError aError);
-
   /**
    * This message is only used on X11 platforms.
    *
    * Send a dup of the plugin process's X socket to the parent
    * process.  In theory, this scheme keeps the plugin's X resources
    * around until after both the plugin process shuts down *and* the
    * parent process closes the dup fd.  This is used to prevent the
    * parent process from crashing on X errors if, e.g., the plugin

--- a/dom/plugins/ipc/PluginModuleParent.cpp
+++ b/dom/plugins/ipc/PluginModuleParent.cpp
@@ -2263,39 +2263,25 @@ PluginModuleChromeParent::NP_Initialize(
     }
     else if (*error != NPERR_NO_ERROR) {
         Close();
         return NS_ERROR_FAILURE;
     }
     TimeStamp callNpInitEnd = TimeStamp::Now();
     mTimeBlocked += (callNpInitEnd - callNpInitStart);
 
-    RecvNP_InitializeResult(*error);
-
-    return NS_OK;
-}
-
-mozilla::ipc::IPCResult
-PluginModuleParent::RecvNP_InitializeResult(const NPError& aError)
-{
-    if (aError != NPERR_NO_ERROR) {
+    if (*error != NPERR_NO_ERROR) {
         OnInitFailure();
-        return IPC_OK();
+        return NS_OK;
     }
 
     SetPluginFuncs(mNPPIface);
 
     mNPInitialized = true;
-    return IPC_OK();
-}
-
-mozilla::ipc::IPCResult
-PluginModuleChromeParent::RecvNP_InitializeResult(const NPError& aError)
-{
-    return PluginModuleParent::RecvNP_InitializeResult(aError);
+    return NS_OK;
 }
 
 #else
 
 nsresult
 PluginModuleParent::NP_Initialize(NPNetscapeFuncs* bFuncs, NPError* error)
 {
     PLUGIN_LOG_DEBUG_METHOD;
@@ -2349,37 +2335,19 @@ PluginModuleChromeParent::NP_Initialize(
 
     TimeStamp callNpInitStart = TimeStamp::Now();
     if (!CallNP_Initialize(settings, error)) {
         Close();
         return NS_ERROR_FAILURE;
     }
     TimeStamp callNpInitEnd = TimeStamp::Now();
     mTimeBlocked += (callNpInitEnd - callNpInitStart);
-    RecvNP_InitializeResult(*error);
-    return NS_OK;
-}
-
-mozilla::ipc::IPCResult
-PluginModuleParent::RecvNP_InitializeResult(const NPError& aError)
-{
-    if (aError != NPERR_NO_ERROR) {
-        OnInitFailure();
-        return IPC_OK();
-    }
-
-    mNPInitialized = true;
-    return IPC_OK();
-}
-
-mozilla::ipc::IPCResult
-PluginModuleChromeParent::RecvNP_InitializeResult(const NPError& aError)
-{
+
     bool ok = true;
-    if (aError == NPERR_NO_ERROR) {
+    if (*error == NPERR_NO_ERROR) {
         // Initialization steps for (e10s && !asyncInit) || !e10s
 #if defined XP_WIN
         // Send the info needed to join the browser process's audio session to
         // the plugin process.
         nsID id;
         nsString sessionName;
         nsString iconPath;
 
@@ -2390,19 +2358,26 @@ PluginModuleChromeParent::RecvNP_Initial
 #endif
 
 #ifdef MOZ_CRASHREPORTER_INJECTOR
         InitializeInjector();
 #endif
     }
 
     if (!ok) {
-        return IPC_FAIL_NO_REASON(this);
+        return NS_ERROR_FAILURE;
     }
-    return PluginModuleParent::RecvNP_InitializeResult(aError);
+
+    if (*error != NPERR_NO_ERROR) {
+        OnInitFailure();
+        return NS_OK;
+    }
+
+    mNPInitialized = true;
+    return NS_OK;
 }
 
 #endif
 
 bool
 PluginModuleParent::RemovePendingSurrogate(
                             const RefPtr<PluginAsyncSurrogate>& aSurrogate)
 {

--- a/dom/plugins/ipc/PluginModuleParent.h
+++ b/dom/plugins/ipc/PluginModuleParent.h
@@ -173,19 +173,16 @@ protected:
     RecvPopCursor() override;
 
     virtual mozilla::ipc::IPCResult
     RecvNPN_SetException(const nsCString& aMessage) override;
 
     virtual mozilla::ipc::IPCResult
     RecvNPN_ReloadPlugins(const bool& aReloadPages) override;
 
-    virtual mozilla::ipc::IPCResult
-    RecvNP_InitializeResult(const NPError& aError) override;
-
     static BrowserStreamParent* StreamCast(NPP instance, NPStream* s,
                                            PluginAsyncSurrogate** aSurrogate = nullptr);
 
     virtual mozilla::ipc::IPCResult
     AnswerNPN_SetValue_NPPVpluginRequiresAudioDeviceChanges(
                                         const bool& shouldRegister,
                                         NPError* result) override;
 
@@ -511,19 +508,16 @@ class PluginModuleChromeParent
     OnHangUIContinue();
 
     void
     EvaluateHangUIState(const bool aReset);
 #endif // XP_WIN
 
     virtual bool WaitForIPCConnection() override;
 
-    virtual mozilla::ipc::IPCResult
-    RecvNP_InitializeResult(const NPError& aError) override;
-
     void CachedSettingChanged();
 
     virtual mozilla::ipc::IPCResult
     AnswerGetKeyState(const int32_t& aVirtKey, int16_t* aRet) override;
 
     // Proxy GetOpenFileName/GetSaveFileName on Windows.
     virtual mozilla::ipc::IPCResult
     AnswerGetFileName(const GetFileNameFunc& aFunc,