Only send the client-side phishing model to a renderer if its profile has SafeBrowsing enabled.

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 "googleurl/src/gurl.h"
 #include "ipc/ipc_message_macros.h"
 
 #define IPC_MESSAGE_START SafeBrowsingMsgStart
@@ skipping 26 matching lines @@
                     std::string /* encoded ClientPhishingRequest proto */)
 
 // Send part of the DOM to the browser, to be used in a malware report.
 IPC_MESSAGE_ROUTED1(SafeBrowsingHostMsg_MalwareDOMDetails,
                     std::vector<SafeBrowsingHostMsg_MalwareDOMDetails_Node>)
 
 // SafeBrowsing client-side detection messages sent from the browser to the
 // renderer.
 
 // A classification model for client-side phishing detection.
-// The string is an encoded safe_browsing::ClientSideModel protocol buffer.
+// 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 */)
 
 // Request a DOM tree when a malware interstitial is shown.
 IPC_MESSAGE_ROUTED0(SafeBrowsingMsg_GetMalwareDOMDetails)
 
 // Tells the renderer to begin phishing detection for the given toplevel URL
 // which it has started loading.
 IPC_MESSAGE_ROUTED1(SafeBrowsingMsg_StartPhishingDetection,
                     GURL)