Bug 1361000 - Log a deprecation warning to the web console upon use of EME in an insecure context. r=bz

Preliminary telemetry indicated 15% of users of EME are in an insecure
context. We'd better log a warning to the web console to inform authors
that their sites will stop working, rather than just breaking them!

MozReview-Commit-ID: CZasdbcC1jS

--HG--
extra : rebase_source : 685a36be1601215aff4e962fd206d1332abbff79

dom/base/Navigator.cpp

@@ -69,6 +69,7 @@
 #include "nsStreamUtils.h"
 #include "WidgetUtils.h"
 #include "nsIPresentationService.h"
+#include "nsIScriptError.h"
 
 #include "mozilla/dom/MediaDevices.h"
 #include "MediaManager.h"
@@ -2024,6 +2025,22 @@ Navigator::RequestMediaKeySystemAccess(const nsAString& aKeySystem,
   Telemetry::Accumulate(Telemetry::MEDIA_EME_SECURE_CONTEXT,
                         mWindow->IsSecureContext());
 
+  if (!mWindow->IsSecureContext()) {
+    nsIDocument* doc = mWindow->GetExtantDoc();
+    nsString uri;
+    if (doc) {
+      doc->GetDocumentURI(uri);
+    }
+    const char16_t* params[] = { uri.get() };
+    nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
+                                    NS_LITERAL_CSTRING("Media"),
+                                    doc,
+                                    nsContentUtils::eDOM_PROPERTIES,
+                                    "MediaEMEInsecureContextDeprecatedWarning",
+                                    params,
+                                    ArrayLength(params));
+  }
+
   nsCOMPtr<nsIGlobalObject> go = do_QueryInterface(mWindow);
   RefPtr<DetailedPromise> promise =
     DetailedPromise::Create(go, aRv,

dom/locales/en-US/chrome/dom/dom.properties

@@ -145,6 +145,8 @@ MediaRecorderMultiTracksNotSupported=MediaRecorder does not support recording mu
 MediaStreamAddTrackDifferentAudioChannel=MediaStreamTrack %S could not be added since it belongs to a different AudioChannel.
 # LOCALIZATION NOTE: Do not translate "MediaStream", "stop()" and "MediaStreamTrack"
 MediaStreamStopDeprecatedWarning=MediaStream.stop() is deprecated and will soon be removed. Use MediaStreamTrack.stop() instead.
+# LOCALIZATION NOTE: %S is the URL of the web page which is not served on HTTPS and thus is not encrypted and considered insecure.
+MediaEMEInsecureContextDeprecatedWarning=Using Encrypted Media Extensions at %S on an insecure (i.e. non-HTTPS) context is deprecated and will soon be removed. You should consider switching to a secure origin such as HTTPS.
 # LOCALIZATION NOTE: Do not translate "DOMException", "code" and "name"
 DOMExceptionCodeWarning=Use of DOMException’s code attribute is deprecated. Use name instead.
 # LOCALIZATION NOTE: Do not translate "__exposedProps__"