Backed out changeset 939ecf1b80cb (bug 1398102) for failing mda's dom/media/test/test_can_play_type_wave.html. r=backout

dom/html/HTMLMediaElement.cpp

@@ -4647,17 +4647,6 @@ HTMLMediaElement::GetCanPlay(const nsAString& aType,
     // demuxer can handle VP9 in fragmented MP4.
     return CANPLAY_NO;
   }
-  if (status == CANPLAY_YES &&
-      (*containerType).ExtendedType().Codecs().IsEmpty()) {
-    // Per spec: 'Generally, a user agent should never return "probably" for a
-    // type that allows the `codecs` parameter if that parameter is not present.'
-    // As all our currently-supported types allow for `codecs`, we can do this
-    // check here.
-    // TODO: Instead, missing `codecs` should be checked in each decoder's
-    // `IsSupportedType` call from `CanHandleCodecsType()`.
-    // See bug 1399023.
-    return CANPLAY_MAYBE;
-  }
   return status;
 }
 
@@ -4675,12 +4664,10 @@ HTMLMediaElement::CanPlayType(const nsAString& aType, nsAString& aResult)
   case CANPLAY_YES:
     aResult.AssignLiteral("probably");
     break;
+  default:
   case CANPLAY_MAYBE:
     aResult.AssignLiteral("maybe");
     break;
-  default:
-    MOZ_ASSERT_UNREACHABLE("Unexpected case.");
-    break;
   }
 
   LOG(LogLevel::Debug, ("%p CanPlayType(%s) = \"%s\"", this,

testing/web-platform/meta/html/semantics/embedded-content/media-elements/mime-types/canPlayType.html.ini

@@ -1,5 +1,10 @@
 [canPlayType.html]
   type: testharness
+  [audio/mp4 (optional)]
+    expected:
+      if not debug and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
+      if debug and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
+
   [audio/mp4; codecs="mp4a.40.2" (optional)]
     expected:
       if not debug and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
@@ -14,6 +19,11 @@
   [video/3gpp; codecs="mp4v.20.8" (optional)]
     expected: FAIL
 
+  [video/mp4 (optional)]
+    expected:
+      if not debug and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
+      if debug and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL
+
   [video/mp4; codecs="mp4a.40.2" (optional)]
     expected:
       if not debug and (os == "win") and (version == "5.1.2600") and (processor == "x86") and (bits == 32): FAIL