Adding Deprecation Message for <keygen>

third_party/WebKit/Source/core/frame/Deprecation.cpp

Index: third_party/WebKit/Source/core/frame/Deprecation.cpp
diff --git a/third_party/WebKit/Source/core/frame/Deprecation.cpp b/third_party/WebKit/Source/core/frame/Deprecation.cpp
index f925991c5e122f461bf492f8762fcb2785f413ea..aa86c10992989a9702efce9e15908af802326d1e 100644
--- a/third_party/WebKit/Source/core/frame/Deprecation.cpp
+++ b/third_party/WebKit/Source/core/frame/Deprecation.cpp
@@ -340,6 +340,9 @@ String Deprecation::deprecationMessage(UseCounter::Feature feature)
     case UseCounter::WebAnimationHyphenatedProperty:
         return replacedWillBeRemoved("Hyphenated naming in Web Animations keyframes", "camelCase", 51, "5650817352728576");
 
+    case UseCounter::HTMLKeygenElement:
+        return willBeRemoved("The <keygen> element", 54, "5716060992962560");
+
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();