mediaplayer: handle decoder error when NuPlayerDecoder gets a NULL buffer from MediaCodec.

MediaCodec could send out message of input buffer available right before it hits an error and clears its buffers.

Bug: 14433407
Change-Id: I32494f4cb2a8537fac12449fd68a74c021f5c9e1
diff --git a/media/libmediaplayerservice/nuplayer/NuPlayerDecoder.cpp b/media/libmediaplayerservice/nuplayer/NuPlayerDecoder.cpp
index 376c93a..d169964 100644
--- a/media/libmediaplayerservice/nuplayer/NuPlayerDecoder.cpp
+++ b/media/libmediaplayerservice/nuplayer/NuPlayerDecoder.cpp
@@ -414,6 +414,11 @@
     sp<ABuffer> buffer;
     mCodec->getInputBuffer(index, &buffer);
 
+    if (buffer == NULL) {
+        handleError(UNKNOWN_ERROR);
+        return false;
+    }
+
     if (index >= mInputBuffers.size()) {
         for (size_t i = mInputBuffers.size(); i <= index; ++i) {
             mInputBuffers.add();