Fix building FFMPEG into Android

media/filters/decoder_selector.h

Index: media/filters/decoder_selector.h
diff --git a/media/filters/decoder_selector.h b/media/filters/decoder_selector.h
index 3ce4df6b201333d54617973dc02c8f7043a53598..17360b37110076779494ff7a83ea976e0cabe05c 100644
--- a/media/filters/decoder_selector.h
+++ b/media/filters/decoder_selector.h
@@ -79,7 +79,7 @@ class MEDIA_EXPORT DecoderSelector {
                      const base::Closure& waiting_for_decryption_key_cb);
 
  private:
-#if !defined(OS_ANDROID)
+#if !defined(DISABLE_FFMPEG_VIDEO_DECODERS)

[xhwang, 2017/05/01 17:10:00]

I saw this when working on the DecoderSelector and got confused. The previous
defined(OS_ANDROID) check isn't super accurate. It's more like "if not
supporting decrypting decoder in the CDM". This is also checked at run-time, but
excluding it at build time will make things slightly simper/faster (I hope).

So I have a question on https://codereview.chromium.org/2808093008, why do you
want to touch Decrypting*Decoder, when you are trying disable FFmpeg*Decoder?
They are two different decoders...

Could you please 

[kraush, 2017/05/01 18:14:59]

Sorry, just to clarify: Are you saying the changes made to
media/filters/decoder_selector.cc in https://codereview.chromium.org/2808093008
seem incorrect, because ffmpeg flags should not guard decrypting_decoder code?

If so, should we loop in rduszynski@opera.com who made those changes?
I'm unfortunately not sure what build configuration they use and thus why those
changes were made :(

   void InitializeDecryptingDecoder();
   void DecryptingDecoderInitDone(bool success);
 #endif