import changes from `dev' branch of rmottola/Arctic-Fox:

- Bug 1148070 - Change nsIClassInfo::getHelperForLanguage() to getScriptableHelper(). r=bholley (30d208d40)
- Bug 1147951, part 3 - Remove unnecessary includes of nsIProgrammingLanguage. r=baku (79a91c51b)
- Bug 1149807 - Remove some unused nsIProgrammingLanguage.h includes. r=froydnj (88a388df4)
- Bug 1147572 - Remove implementation language field from DOM class info. r=jst (3491499e0)
- Bug 1150197 - Remove useless null checks after allocating memory with new from xpcom/threads/; r=froydnj (8e8357735)

xpcom/threads/nsThread.cpp

@@ -18,7 +18,6 @@
 #include "nsMemoryPressure.h"
 #include "nsThreadManager.h"
 #include "nsIClassInfoImpl.h"
-#include "nsIProgrammingLanguage.h"
 #include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "pratom.h"
@@ -124,7 +123,7 @@ nsThreadClassInfo::GetInterfaces(uint32_t* aCount, nsIID*** aArray)
 }
 
 NS_IMETHODIMP
-nsThreadClassInfo::GetHelperForLanguage(uint32_t aLang, nsISupports** aResult)
+nsThreadClassInfo::GetScriptableHelper(nsIXPCScriptable** aResult)
 {
   *aResult = nullptr;
   return NS_OK;
@@ -151,13 +150,6 @@ nsThreadClassInfo::GetClassID(nsCID** aResult)
   return NS_OK;
 }
 
-NS_IMETHODIMP
-nsThreadClassInfo::GetImplementationLanguage(uint32_t* aResult)
-{
-  *aResult = nsIProgrammingLanguage::CPLUSPLUS;
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsThreadClassInfo::GetFlags(uint32_t* aResult)
 {
@@ -550,9 +542,6 @@ nsThread::DispatchInternal(nsIRunnable* aEvent, uint32_t aFlags,
 
     nsRefPtr<nsThreadSyncDispatch> wrapper =
       new nsThreadSyncDispatch(thread, aEvent);
-    if (!wrapper) {
-      return NS_ERROR_OUT_OF_MEMORY;
-    }
     nsresult rv = PutEvent(wrapper, aTarget);
     // Don't wait for the event to finish if we didn't dispatch it...
     if (NS_FAILED(rv)) {
@@ -630,9 +619,6 @@ nsThread::Shutdown()
   // Set mShutdownContext and wake up the thread in case it is waiting for
   // events to process.
   nsCOMPtr<nsIRunnable> event = new nsThreadShutdownEvent(this, &context);
-  if (!event) {
-    return NS_ERROR_OUT_OF_MEMORY;
-  }
   // XXXroc What if posting the event fails due to OOM?
   PutEvent(event, nullptr);