Adding check for MIME types that do not take codecs parameter

content/renderer/renderer_webkitplatformsupport_impl.cc

Index: content/renderer/renderer_webkitplatformsupport_impl.cc
diff --git a/content/renderer/renderer_webkitplatformsupport_impl.cc b/content/renderer/renderer_webkitplatformsupport_impl.cc
index ca92d5e5568cd56aa2d2c99ab959a19ddc66828d..627b762e12bce64318955ba5544e116ffa13ddea 100644
--- a/content/renderer/renderer_webkitplatformsupport_impl.cc
+++ b/content/renderer/renderer_webkitplatformsupport_impl.cc
@@ -432,18 +432,17 @@ RendererWebKitPlatformSupportImpl::MimeRegistry::supportsMediaMIMEType(
 
   // Check list of strict codecs to see if it is supported.
   if (net::IsStrictMediaMimeType(mime_type_ascii)) {
-    // We support the container, but no codecs were specified.
-    if (codecs.isNull())
-      return MayBeSupported;
-
     // Check if the codecs are a perfect match.
     std::vector<std::string> strict_codecs;
     net::ParseCodecString(ToASCIIOrEmpty(codecs), &strict_codecs, false);
-    if (!net::IsSupportedStrictMediaMimeType(mime_type_ascii, strict_codecs))
-      return IsNotSupported;
+    if (net::IsSupportedStrictMediaMimeType(mime_type_ascii, strict_codecs))

[Ryan Sleevi, 2014/04/18 01:57:41]

How does this work without you also requiring to change AreSupportedCodecs?

ParseCodecString results in an empty strict_codecs

net::IsSupportedStrictMediaMimeType finds "audio/mp3" within strict_format_map_,
so it calls AreSupportedCodecs(), with the first parameter as an empty vector
(as no supported codecs) and the second parameter as an empty vector (as it's
the above strict_codecs parameter)

AreSupportedCodecs() iterates through codecs (empty) to see if any of them are
within supported_codecs - but this is a no-op. As a result, it hits the final
condition - "return !codecs.empty()". However, codecs.empty() == true,
!codecs.empty() == false, therefore AreSupportedCodecs() should return false, so
shouldn't we be hidding line 441-443?

Have you tested this code? Am I missing something? Is it creating a codecs_out
with an empty string instead of an empty vector?

[amogh.bihani, 2014/04/21 06:10:56]

I'm sorry I missed this. I did test this code. The testcases were passing. But
they were passing because USE_PROPRIETARY_CODECS was not enabled in my system.

We cannot remove lines 441 to 443 as "maybe" is a valid response and we need to
give this when no codecs are present for the containers which expect 'codecs'
parameter.

+      return IsSupported;
 
-    // Good to go!
-    return IsSupported;
+    // We support the container, but no codecs were specified.
+    if (codecs.isNull())
+      return MayBeSupported;
+
+    return IsNotSupported;
   }
 
   // If we don't recognize the codec, it's possible we support it.