Bug 1333979 - Adds a check in the WidevineVideoDecoder before shutting down r=cpearce

DeinitializeDecoder will now only be called if InitializeDecoder has been called first

MozReview-Commit-ID: 93WexomWp92

--HG--
extra : rebase_source : 96dfa5666041340d56fbfce7a46fb7f8f67181dc

dom/media/gmp/widevine-adapter/WidevineVideoDecoder.cpp

@@ -383,10 +383,18 @@ void
 WidevineVideoDecoder::DecodingComplete()
 {
   Log("WidevineVideoDecoder::DecodingComplete()");
+
   if (mCDMWrapper) {
-    CDM()->DeinitializeDecoder(kStreamTypeVideo);
+    // mCallback will be null if the decoder has not been fully initialized.
+    if (mCallback) {
+      CDM()->DeinitializeDecoder(kStreamTypeVideo);
+    } else {
+      Log("WideVineDecoder::DecodingComplete() Decoder was not fully initialized!");
+    }
+
     mCDMWrapper = nullptr;
   }
+
   // Release that corresponds to AddRef() in constructor.
   Release();
 }

dom/media/gmp/widevine-adapter/WidevineVideoDecoder.h

@@ -59,7 +59,7 @@ private:
   RefPtr<CDMWrapper> mCDMWrapper;
   RefPtr<MediaByteBuffer> mExtraData;
   RefPtr<MediaByteBuffer> mAnnexB;
-  GMPVideoDecoderCallback* mCallback;
+  GMPVideoDecoderCallback* mCallback = nullptr;
   std::map<uint64_t, uint64_t> mFrameDurations;
   bool mSentInput;
   GMPVideoCodecType mCodecType;