Bug 1259916: [MSE] P2. Bump audio source buffer eviction threshold to 30MB. r=gerald

20MB appears to work, but just to be safe until we get confirmation from YouTube on what is a safe value to use.

MozReview-Commit-ID: BnGaVLeCRJ5

--HG--
extra : rebase_source : 6333dd4c8dbd6f846344218dd50124797fc5cb23

dom/media/mediasource/TrackBuffersManager.cpp

@@ -103,7 +103,7 @@ TrackBuffersManager::TrackBuffersManager(MediaSourceDecoder* aParentDecoder,
   , mVideoEvictionThreshold(Preferences::GetUint("media.mediasource.eviction_threshold.video",
                                                  100 * 1024 * 1024))
   , mAudioEvictionThreshold(Preferences::GetUint("media.mediasource.eviction_threshold.audio",
-                                                 15 * 1024 * 1024))
+                                                 30 * 1024 * 1024))
   , mEvictionOccurred(false)
   , mMonitor("TrackBuffersManager")
 {