Remove HttpAuth::Scheme enum in favor of a string.

net/http/http_auth_cache.h

Index: net/http/http_auth_cache.h
diff --git a/net/http/http_auth_cache.h b/net/http/http_auth_cache.h
index 3880dbf70f311043ca0a42d48cf42d3d4aa08e31..f962b66d317eb05df9e8fc10b1963bb0b18d2dbd 100644
--- a/net/http/http_auth_cache.h
+++ b/net/http/http_auth_cache.h
@@ -46,7 +46,7 @@ class NET_EXPORT_PRIVATE HttpAuthCache {
   //   returns  - the matched entry or NULL.
   Entry* Lookup(const GURL& origin,
                 const std::string& realm,
-                HttpAuth::Scheme scheme);
+                const std::string& scheme);
 
   // Find the entry on server |origin| whose protection space includes
   // |path|. This uses the assumption in RFC 2617 section 2 that deeper
@@ -70,7 +70,7 @@ class NET_EXPORT_PRIVATE HttpAuthCache {
   //   returns    - the entry that was just added/updated.
   Entry* Add(const GURL& origin,
              const std::string& realm,
-             HttpAuth::Scheme scheme,
+             const std::string& scheme,
              const std::string& auth_challenge,
              const AuthCredentials& credentials,
              const std::string& path);
@@ -84,7 +84,7 @@ class NET_EXPORT_PRIVATE HttpAuthCache {
   //   returns    - true if an entry was removed.
   bool Remove(const GURL& origin,
               const std::string& realm,
-              HttpAuth::Scheme scheme,
+              const std::string& scheme,
               const AuthCredentials& credentials);
 
   // Updates a stale digest entry on server |origin| for realm |realm| and
@@ -94,7 +94,7 @@ class NET_EXPORT_PRIVATE HttpAuthCache {
   // cache, false otherwise.
   bool UpdateStaleChallenge(const GURL& origin,
                             const std::string& realm,
-                            HttpAuth::Scheme scheme,
+                            const std::string& scheme,
                             const std::string& auth_challenge);
 
   // Copies all entries from |other| cache.
@@ -120,7 +120,7 @@ class NET_EXPORT_PRIVATE HttpAuthCache::Entry {
   }
 
   // The authentication scheme of the challenge.
-  HttpAuth::Scheme scheme() const {
+  std::string scheme() const {
     return scheme_;
   }
 
@@ -166,7 +166,7 @@ class NET_EXPORT_PRIVATE HttpAuthCache::Entry {
   // |origin_| contains the {protocol, host, port} of the server.
   GURL origin_;
   std::string realm_;
-  HttpAuth::Scheme scheme_;
+  std::string scheme_;
 
   // Identity.
   std::string auth_challenge_;