Issue #80 - De-unify dom/media part 1 (updated reland)

This de-unifies up to and including dom/media/platforms with the exception of
dom/media/platforms/wmf, because that one throws weird errors in the Win
SDK which don't have a clear cause (yet)

dom/media/platforms/agnostic/TheoraDecoder.cpp

@@ -10,6 +10,7 @@
 #include "nsError.h"
 #include "TimeUnits.h"
 #include "mozilla/PodOperations.h"
+#include "mozilla/SyncRunnable.h"
 
 #include <algorithm>
 

dom/media/platforms/agnostic/eme/moz.build

@@ -11,7 +11,7 @@ EXPORTS += [
     'SamplesWaitingForKey.h',
 ]
 
-UNIFIED_SOURCES += [
+SOURCES += [
     'EMEAudioDecoder.cpp',
     'EMEDecoderModule.cpp',
     'EMEVideoDecoder.cpp',

dom/media/platforms/agnostic/gmp/GMPVideoDecoder.cpp

@@ -10,6 +10,7 @@
 #include "prsystem.h"
 #include "MediaData.h"
 #include "GMPDecoderModule.h"
+#include "MP4Decoder.h"
 #include "VPXDecoder.h"
 
 namespace mozilla {

dom/media/platforms/agnostic/gmp/moz.build

@@ -11,7 +11,7 @@ EXPORTS += [
     'MediaDataDecoderProxy.h',
 ]
 
-UNIFIED_SOURCES += [
+SOURCES += [
     'GMPAudioDecoder.cpp',
     'GMPDecoderModule.cpp',
     'GMPVideoDecoder.cpp',