Bug 1336367 - Rename TestTrackEncoder to TestAudioTrackEncoder. r=pehrsons

The TestTrackEncoder file only contained audio encoder tests. This makes the
distinction between the already existing TestVideoTrackEncoder and these audio
tests clearer.

MozReview-Commit-ID: KmM616S72Gm

--HG--
rename : dom/media/gtest/TestTrackEncoder.cpp => dom/media/gtest/TestAudioTrackEncoder.cpp
extra : rebase_source : abd0965fd27ef0f51575ac20e908b4cc908bca47

dom/media/gtest/moz.build

@@ -11,6 +11,7 @@ UNIFIED_SOURCES += [
     'TestAudioMixer.cpp',
     'TestAudioPacketizer.cpp',
     'TestAudioSegment.cpp',
+    'TestAudioTrackEncoder.cpp',
     'TestBlankVideoDataCreator.cpp',
     'TestGMPCrossOrigin.cpp',
     'TestGMPRemoveAndDelete.cpp',
@@ -22,7 +23,6 @@ UNIFIED_SOURCES += [
     'TestMP3Demuxer.cpp',
     'TestMP4Demuxer.cpp',
     'TestRust.cpp',
-    'TestTrackEncoder.cpp',
     'TestVideoSegment.cpp',
     'TestVideoUtils.cpp',
     'TestVPXDecoding.cpp',