Remove disable warnings compile flag in safebrowsing component, and fix some type win64 type errors…

components/safe_browsing/renderer/BUILD.gn

 # Copyright 2017 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.
 
 import("//build/config/features.gni")
 
 source_set("renderer") {
   if (safe_browsing_mode != 0) {
     sources = [
       "threat_dom_details.cc",
       "threat_dom_details.h",
     ]
     deps = [
       "//base",
       "//components/safe_browsing/common:common",
       "//content/public/renderer",
       "//ipc",
       "//third_party/WebKit/public:blink",
       "//url/ipc:url_ipc",
     ]
-    if (is_win) {
-      cflags = [ "/wd4267" ]  # conversion from 'size_t' to 'int' on x64 (crbug.com/702773)
-    }
   }
 }