Remove an unnecessary loop when converting scheme in NavigatorContentUtils

This CL is simple refactoring in order not to use an unnecessary loop
in isSchemeWhitelisted() function.

Additionally the spec url is updated because current one is outdated.

TEST=http/tests/navigatorcontentutils
BUG=none

Review-Url: https://codereview.chromium.org/2083363003
Cr-Commit-Position: refs/heads/master@{#401832}
diff --git a/third_party/WebKit/Source/modules/navigatorcontentutils/NavigatorContentUtils.cpp b/third_party/WebKit/Source/modules/navigatorcontentutils/NavigatorContentUtils.cpp
index 8373c5d..ccb2d8f 100644
--- a/third_party/WebKit/Source/modules/navigatorcontentutils/NavigatorContentUtils.cpp
+++ b/third_party/WebKit/Source/modules/navigatorcontentutils/NavigatorContentUtils.cpp
@@ -107,9 +107,7 @@
         initCustomSchemeHandlerWhitelist();
 
     StringBuilder builder;
-    unsigned length = scheme.length();
-    for (unsigned i = 0; i < length; ++i)
-        builder.append(toASCIILower(scheme[i]));
+    builder.append(scheme.lower().ascii().data());
 
     return schemeWhitelist->contains(builder.toString());
 }
diff --git a/third_party/WebKit/Source/modules/navigatorcontentutils/NavigatorContentUtils.idl b/third_party/WebKit/Source/modules/navigatorcontentutils/NavigatorContentUtils.idl
index b5a05db0..03b43ee 100644
--- a/third_party/WebKit/Source/modules/navigatorcontentutils/NavigatorContentUtils.idl
+++ b/third_party/WebKit/Source/modules/navigatorcontentutils/NavigatorContentUtils.idl
@@ -18,7 +18,7 @@
     Boston, MA 02110-1301, USA.
 */
 
-// http://www.w3.org/TR/html5/system-state-and-capabilities.html#custom-handlers
+// https://www.w3.org/TR/html5/webappapis.html#navigatorcontentutils
 partial interface Navigator {
     [RuntimeEnabled=NavigatorContentUtils, RaisesException] void registerProtocolHandler(DOMString scheme, DOMString url, DOMString title);
     [RuntimeEnabled=CustomSchemeHandler, RaisesException] DOMString isProtocolHandlerRegistered(DOMString scheme, DOMString url);