MediaMuxer: throw exception if create() fails for muxer

This patch also updates the documentation for MediaMuxer()

Bug: 146417874
Test: atest CtsMediaV2TestCases:MuxerTest
Test: atest CtsMediaV2TestCases:MuxerUnitTest
Test: CtsMediaMuxerTestCases

Change-Id: Ia07a7e6864d6c27476b960069a6f4e8ac0de8255
diff --git a/media/jni/android_media_MediaMuxer.cpp b/media/jni/android_media_MediaMuxer.cpp
index 2679176..b664325 100644
--- a/media/jni/android_media_MediaMuxer.cpp
+++ b/media/jni/android_media_MediaMuxer.cpp
@@ -165,7 +165,11 @@
 
     MediaMuxer::OutputFormat fileFormat =
         static_cast<MediaMuxer::OutputFormat>(format);
-    sp<MediaMuxer> muxer = new MediaMuxer(fd, fileFormat);
+    sp<MediaMuxer> muxer = MediaMuxer::create(fd, fileFormat);
+    if (muxer == nullptr) {
+        jniThrowException(env, "java/lang/IllegalArgumentException", "Muxer creation failed");
+        return 0;
+    }
     muxer->incStrong(clazz);
     return reinterpret_cast<jlong>(muxer.get());
 }