Bug 1515471 - Tidy mp4parser test cases. r=jya

Driveby tidying:
- Tidy and clarify comment impacted by global clang-formatting.
- Update comments on two test cases disabled by bug 1224019. These tests no
  longer have log spam issues, and have some value as sanity tests, but remain
  disabled due to being resource hogs. Comments indicate this.

Differential Revision: https://phabricator.services.mozilla.com/D15441

--HG--
extra : moz-landing-system : lando

dom/media/gtest/mp4_demuxer/TestParser.cpp

@@ -166,8 +166,8 @@ struct TestFileData {
 };
 
 static const TestFileData testFiles[] = {
-    // filename                     parse #V dur   w    h  #A dur  crypt  off
-    // moof  headr  audio_profile
+    // filename parses? #V hasVideoIndex vDur w h #A aDur hasCrypto? moofOffset
+    // validMoof? hasHeader? audio_profile
     {"test_case_1156505.mp4", false, 0, false, -1, 0, 0, 0, -1, false, 152,
      false, false, 0},  // invalid ''trak box
     {"test_case_1181213.mp4", true, 1, true, 416666, 320, 240, 1, 477460, true,
@@ -349,10 +349,13 @@ TEST(MP4Metadata, test_case_mp4) {
   }
 }
 
-// Bug 1224019: This test produces way to much output, disabling for now.
+// This test was disabled by Bug 1224019 for producing way too much output.
+// This test no longer produces such output, as we've moved away from
+// stagefright, but it does take a long time to run. I can be useful to enable
+// as a sanity check on changes to the parser, but is too taxing to run as part
+// of normal test execution.
 #if 0
-TEST(MPEG4Metadata, test_case_mp4_subsets)
-{
+TEST(MP4Metadata, test_case_mp4_subsets) {
   static const size_t step = 1u;
   for (size_t test = 0; test < ArrayLength(testFiles); ++test) {
     nsTArray<uint8_t> buffer = ReadTestFile(testFiles[test].mFilename);
@@ -433,10 +436,13 @@ TEST(MoofParser, test_case_mp4) {
   }
 }
 
-// Bug 1224019: This test produces way to much output, disabling for now.
+// This test was disabled by Bug 1224019 for producing way too much output.
+// This test no longer produces such output, as we've moved away from
+// stagefright, but it does take a long time to run. I can be useful to enable
+// as a sanity check on changes to the parser, but is too taxing to run as part
+// of normal test execution.
 #if 0
-TEST(MoofParser, test_case_mp4_subsets)
-{
+TEST(MoofParser, test_case_mp4_subsets) {
   const size_t step = 1u;
   for (size_t test = 0; test < ArrayLength(testFiles); ++test) {
     nsTArray<uint8_t> buffer = ReadTestFile(testFiles[test].mFilename);