Bug 1314858 - Add MP4Decoder::IsAAC. r=gerald

We have this for H.264, so we may as well have it for AAC too.

MozReview-Commit-ID: 2k64ANJGUNN

--HG--
extra : rebase_source : 6fe2543788afd26682d31c0ec45b9ac80e501ab1

dom/media/fmp4/MP4Decoder.cpp

@@ -168,6 +168,13 @@ MP4Decoder::IsH264(const nsACString& aMimeType)
          aMimeType.EqualsLiteral("video/avc");
 }
 
+/* static */
+bool
+MP4Decoder::IsAAC(const nsACString& aMimeType)
+{
+  return aMimeType.EqualsLiteral("audio/mp4a-latm");
+}
+
 /* static */
 bool
 MP4Decoder::IsEnabled()

dom/media/fmp4/MP4Decoder.h

@@ -40,6 +40,11 @@ public:
   // space matters.
   static bool IsH264(const nsACString& aMimeType);
 
+  // Return true if aMimeType is a one of the strings used by our demuxers to
+  // identify AAC. Does not parse general content type strings, i.e. white
+  // space matters.
+  static bool IsAAC(const nsACString& aMimeType);
+
   // Returns true if the MP4 backend is preffed on.
   static bool IsEnabled();