Fix segmented WebVTT test.

The test added in the previous CL was broken due to a rebase on another
change.  This subtly changed some of the byte offsets that broke the
test.  This wasn't caught since I didn't rebase and re-run the tests
before merging.

Change-Id: Id7e4c7688278eae37da1a14f1648263b4dda98cd

packager/app/test/testdata/segmented-webvtt-with-language-override/output.mpd

@@ -4,7 +4,7 @@
   <Period id="0" start="PT0S">
     <AdaptationSet id="0" contentType="text" lang="pt" segmentAlignment="true">
       <Role schemeIdUri="urn:mpeg:dash:role:2011" value="subtitle"/>
-      <Representation id="0" bandwidth="2024" codecs="wvtt" mimeType="application/mp4">
+      <Representation id="0" bandwidth="2056" codecs="wvtt" mimeType="application/mp4">
         <SegmentTemplate timescale="1000" initialization="bear-english-text-init.mp4" media="bear-english-text-$Number$.m4s" startNumber="1">
           <SegmentTimeline>
             <S t="0" d="1000" r="4"/>

packager/media/base/byte_queue.cc

@@ -28,7 +28,6 @@ void ByteQueue::Reset() {
 
 void ByteQueue::Push(const uint8_t* data, int size) {
   DCHECK(data);
-  DCHECK_GT(size, 0);
 
   size_t size_needed = used_ + size;