Bug 1207376 - Check whether H264Converter created its decoder successfully. r=jya

dom/media/platforms/PlatformDecoderModule.cpp

@@ -242,12 +242,20 @@ PlatformDecoderModule::CreateDecoder(const TrackInfo& aConfig,
   }
 
   if (H264Converter::IsH264(aConfig)) {
-    m = new H264Converter(this,
+    nsRefPtr<H264Converter> h
+      = new H264Converter(this,
                           *aConfig.GetAsVideoInfo(),
                           aLayersBackend,
                           aImageContainer,
                           aTaskQueue,
                           callback);
+    const nsresult rv = h->GetLastError();
+    if (NS_SUCCEEDED(rv) || rv == NS_ERROR_NOT_INITIALIZED) {
+      // The H264Converter either successfully created the wrapped decoder,
+      // or there wasn't enough AVCC data to do so. Otherwise, there was some
+      // problem, for example WMF DLLs were missing.
+      m = h.forget();
+    }
   } else if (!hasPlatformDecoder && VPXDecoder::IsVPX(aConfig.mMimeType)) {
     m = new VPXDecoder(*aConfig.GetAsVideoInfo(),
                        aImageContainer,

dom/media/platforms/wrappers/H264Converter.h

@@ -38,6 +38,7 @@ public:
 
   // Return true if mimetype is H.264.
   static bool IsH264(const TrackInfo& aConfig);
+  nsresult GetLastError() const { return mLastError; }
 
 private:
   // Will create the required MediaDataDecoder if need AVCC and we have a SPS NAL.