Deprecate MediaStream label, ended attributes and stop() method

Source/core/frame/UseCounter.cpp

Index: Source/core/frame/UseCounter.cpp
diff --git a/Source/core/frame/UseCounter.cpp b/Source/core/frame/UseCounter.cpp
index 0508a133bf78bf741cd430c2065c5814e5433eba..6e00d7724a3f7b6f647e57807c61879f8c00da52 100644
--- a/Source/core/frame/UseCounter.cpp
+++ b/Source/core/frame/UseCounter.cpp
@@ -938,6 +938,13 @@ String UseCounter::deprecationMessage(Feature feature)
     case SVGSMILAnimationInImageRegardlessOfCache:
         return "SVG's SMIL animations (<animate>, <set>, etc.) are deprecated and will be removed. Please use CSS animations or Web animations instead.";
 
+    case MediaStreamLabel:
+        return "'MediaStream.label' is deprecated. See http://w3c.github.io/mediacapture-main/getusermedia.html#idl-def-MediaStream for more details.";

[philipj_slow, 2015/06/24 10:18:17]

Please add a blank line after every return like above in this file.

I think that we should set a date for the removal so that people know to take it
seriously. If this lands this week the deprecation will be in M45, and two
release cycles ought to be enough, so removal in M47. In other words, this
message:
"'MediaStream.label' is deprecated and will be removed in M47, around November
2015. Please use 'MediaStream.id' instead.";

And similarly for the below.

[shiva.jm, 2015/06/24 12:06:42]

Done.

+    case MediaStreamStop:
+        return "'MediaStream.stop()' is deprecated. Please use MediaStream.active attribute instead.";
+    case MediaStreamEnded:
+        return "'MediaStream.ended' is deprecated. Please use MediaStream.active attribute instead.";
+
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();