Avoid calling setDataSource twice for videos

It's pretty expensive to do, so we're wasting time for videos. If
setDataSource is called with a non-video, it will throw an exception
which in turn will cause us to move on to the next decoder, so the
behavior shouldn't change.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=168390557

library/src/main/java/com/bumptech/glide/load/resource/bitmap/VideoBitmapDecoder.java

@@ -101,16 +101,10 @@ public VideoBitmapDecoder(BitmapPool bitmapPool) {
 
   @Override
   public boolean handles(ParcelFileDescriptor data, Options options) {
-    MediaMetadataRetriever retriever = factory.build();
-    try {
-      retriever.setDataSource(data.getFileDescriptor());
-      return true;
-    } catch (RuntimeException e) {
-      // Throws a generic runtime exception when given invalid data.
-      return false;
-    } finally {
-      retriever.release();
-    }
+    // Calling setDataSource is expensive so avoid doing so unless we're actually called.
+    // For non-videos this isn't any cheaper, but for videos it safes the redundant call and
+    // 50-100ms.
+    return true;
   }
 
   @Override
@@ -134,6 +128,9 @@ public Resource<Bitmap> decode(ParcelFileDescriptor resource, int outWidth, int
       } else {
         result = mediaMetadataRetriever.getFrameAtTime(frameTimeMicros, frameOption);
       }
+    } catch (RuntimeException e) {
+      // MediaMetadataRetriever APIs throw generic runtime exceptions when given invalid data.
+      throw new IOException(e);
     } finally {
       mediaMetadataRetriever.release();
     }