Remove safe_browsing=2 functionality, replace with =3 mode.

chrome/common/safe_browsing/safebrowsing_messages.h

 // Copyright (c) 2011 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.
 
 // Multiply-included message file, so no include guard.
 
 #include <string>
 #include <vector>
 
 #include "ipc/ipc_message_macros.h"
 #include "url/gurl.h"
 
-#if !defined(SAFE_BROWSING_SERVICE)
-#error "Safe browsing should be enabled"
-#endif
-
 #define IPC_MESSAGE_START SafeBrowsingMsgStart
 
 // A node is essentially a frame.
 IPC_STRUCT_BEGIN(SafeBrowsingHostMsg_MalwareDOMDetails_Node)
   // URL of this resource. Can be empty.
   IPC_STRUCT_MEMBER(GURL, url)
 
   // If this resource was in the "src" attribute of a tag, this is the tagname
   // (eg "IFRAME"). Can be empty.
   IPC_STRUCT_MEMBER(std::string, tag_name)
@@ skipping 33 matching lines @@
 // The string is an encoded safe_browsing::ClientSideModel protocol buffer, or
 // empty to disable client-side phishing detection for this renderer.
 IPC_MESSAGE_CONTROL1(SafeBrowsingMsg_SetPhishingModel,
                      std::string /* encoded ClientSideModel proto */)
 
 // Tells the renderer to begin phishing detection for the given toplevel URL
 // which it has started loading.
 IPC_MESSAGE_ROUTED1(SafeBrowsingMsg_StartPhishingDetection,
                     GURL)
 #endif