Bug 1248507 - p1. Pass DecoderDoctorDiagnostics to PDMs&more - r=jya

Pass declared-but-yet-undefined DecoderDoctorDiagnostics pointer to various
routines that contribute to deciding if a media format can be played, and
those that create decoders.

Points where a DecoderDoctorDiagnostics can be injected are currently marked
with "/* DecoderDoctorDiagnostics* */ nullptr", and some will be used in
following patches.

MozReview-Commit-ID: 7u37bvY4CpW

dom/html/HTMLMediaElement.cpp

@@ -2898,7 +2898,8 @@ HTMLMediaElement::GetCanPlay(const nsAString& aType)
   NS_ConvertUTF16toUTF8 mimeTypeUTF8(mimeType);
   return DecoderTraits::CanHandleMediaType(mimeTypeUTF8.get(),
                                            NS_SUCCEEDED(rv),
-                                           codecs);
+                                           codecs,
+           /* DecoderDoctorDiagnostics* */ nullptr);
 }
 
 NS_IMETHODIMP
@@ -2964,7 +2965,9 @@ nsresult HTMLMediaElement::InitializeDecoderForChannel(nsIChannel* aChannel,
   aChannel->GetContentType(mimeType);
   NS_ASSERTION(!mimeType.IsEmpty(), "We should have the Content-Type.");
 
-  RefPtr<MediaDecoder> decoder = DecoderTraits::CreateDecoder(mimeType, this);
+  RefPtr<MediaDecoder> decoder =
+    DecoderTraits::CreateDecoder(mimeType, this,
+                                 /* DecoderDoctorDiagnostics* */ nullptr);
   if (!decoder) {
     nsAutoString src;
     GetCurrentSrc(src);