Remove thumbnails from the ClientSideDetectionService.

chrome/browser/safe_browsing/csd.proto

 // Copyright (c) 2010 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.
 //
 // Client side phishing and malware detection request and response
 // protocol buffers.  Those protocol messages should be kept in sync
 // with the server implementation.
 //
 // If you want to change this protocol definition or you have questions
 // regarding its format please contact chrome-anti-phishing@googlegroups.com.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
 package safe_browsing;
 
 message ClientPhishingRequest {
   // URL that the client visited.  The CGI parameters are stripped by the
   // client.
   required string url = 1;
 
   // Score that was computed on the client.  Value is between 0.0 and 1.0.
   // The larger the value the more likely the url is phishing.
   required float client_score = 2;
-
-  // Thumbnail from the client.  Supports all typical image formats (png, jpg
-  // etc.).
-  required bytes snapshot = 3;
 }
 
 message ClientPhishingResponse {
   required bool phishy = 1;
 }