Bug 1137957 - Fix non-unified build failure in GMPVideoDecoder. r=kinetik

dom/media/fmp4/gmp/GMPAudioDecoder.cpp

@@ -9,7 +9,7 @@
 namespace mozilla {
 
 #if defined(DEBUG)
-static bool IsOnGMPThread()
+bool IsOnGMPThread()
 {
   nsCOMPtr<mozIGeckoMediaPluginService> mps = do_GetService("@mozilla.org/gecko-media-plugin-service;1");
   MOZ_ASSERT(mps);

dom/media/fmp4/gmp/GMPVideoDecoder.cpp

@@ -11,7 +11,7 @@
 namespace mozilla {
 
 #if defined(DEBUG)
-static bool IsOnGMPThread();
+extern bool IsOnGMPThread();
 #endif
 
 void