Remove outdated function mention in comment

The comment referenced a function that no longer exists. Fix it.

Change-Id: Id4b9b1107a07c14bc6e0a7d7283ed0aa67f72557
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2590405
Auto-Submit: Eric Lawrence [MSFT] <ericlaw@microsoft.com>
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Eric Lawrence [MSFT] <ericlaw@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#837128}

chrome/common/extensions/chrome_manifest_url_handlers.h

@@ -19,7 +19,7 @@ namespace chrome_manifest_urls {
 const GURL& GetDevToolsPage(const Extension* extension);
 }
 
-// Stores Chrome URL overrides specified in extensions manifests.
+// Stores Chrome URL overrides specified in extensions' manifests.
 struct URLOverrides : public Extension::ManifestData {
   typedef std::map<const std::string, GURL> URLOverrideMap;
 
@@ -30,7 +30,7 @@ struct URLOverrides : public Extension::ManifestData {
       const Extension* extension);
 
   // A map of chrome:// hostnames (newtab, downloads, etc.) to Extension URLs
-  // which override the handling of those URLs. (see ExtensionOverrideUI).
+  // which override the handling of those URLs.
   URLOverrideMap chrome_url_overrides_;
 };