Unify UUID/GUID generation code across base and blink

chrome/browser/push_messaging/push_messaging_app_identifier.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/push_messaging/push_messaging_app_identifier.h"
 
 #include <string.h>
 
 #include "base/guid.h"
 #include "base/logging.h"
@@ skipping 48 matching lines @@
   // pref is read from the right profile, as prefs defined in a regular profile
   // are visible in the corresponding incognito profile unless overridden.
   // TODO(johnme): Make sure this pref doesn't get out of sync after crashes.
   registry->RegisterDictionaryPref(prefs::kPushMessagingAppIdentifierMap);
 }
 
 // static
 PushMessagingAppIdentifier PushMessagingAppIdentifier::Generate(
     const GURL& origin,
     int64_t service_worker_registration_id) {
-  std::string guid = base::GenerateGUID();
+  // Use uppercase GUID for consistency with GUIDs Push has already sent to GCM.
+  // Also allows detecting case mangling; see code commented "crbug.com/461867".
+  std::string guid = base::ToUpperASCII(base::GenerateGUID());
   CHECK(!guid.empty());
   std::string app_id =
       kPushMessagingAppIdentifierPrefix + origin.spec() + kSeparator + guid;
 
   PushMessagingAppIdentifier app_identifier(app_id, origin,
                                             service_worker_registration_id);
   app_identifier.DCheckValid();
   return app_identifier;
 }
 
@@ skipping 128 matching lines @@
     DCHECK(app_id_.size() > kPrefixLength + suffix_length);
     DCHECK_EQ(origin_, GURL(app_id_.substr(
                            kPrefixLength,
                            app_id_.size() - kPrefixLength - suffix_length)));
     DCHECK_EQ(std::string(1, kSeparator),
               app_id_.substr(app_id_.size() - suffix_length, 1));
   }
   // GUID
   DCHECK(base::IsValidGUID(app_id_.substr(app_id_.size() - kGuidLength)));
 }