Remove case-insensitive matching of usemap attribute.

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 f0bbf76ba7c16a6b5b221d2332cd7c9f08b67d15..07966da0a2cc21a091c2b2102b5f5f9efe966eba 100644
--- a/third_party/WebKit/Source/core/frame/Deprecation.cpp
+++ b/third_party/WebKit/Source/core/frame/Deprecation.cpp
@@ -206,11 +206,6 @@ String Deprecation::deprecationMessage(UseCounter::Feature feature) {
              "deprecated. Please pass the index argument as well: "
              "insertRule(x, 0).";
 
-    case UseCounter::MapNameMatchingASCIICaseless:
-    case UseCounter::MapNameMatchingUnicodeLower:
-      return willBeRemoved("Case-insensitive matching for usemap attribute",
-                           M58, "5760965337415680");
-
     case UseCounter::PrefixedVideoSupportsFullscreen:
       return replacedBy("'HTMLVideoElement.webkitSupportsFullscreen'",
                         "'Document.fullscreenEnabled'");