Implemented a policy for centralized setting of the --disk-cache-dir flag.

chrome/browser/profiles/profile_impl.cc

 // 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.
 
 #include "chrome/browser/profiles/profile_impl.h"
 
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/environment.h"
 #include "base/file_path.h"
@@ skipping 134 matching lines @@
 void GetCacheParameters(ContextType type, FilePath* cache_path,
                         int* max_size) {
   DCHECK(cache_path);
   DCHECK(max_size);
 
   // Override the cache location if specified by the user.
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kDiskCacheDir)) {
     *cache_path = CommandLine::ForCurrentProcess()->GetSwitchValuePath(
         switches::kDiskCacheDir);
   }
+  // And if a policy is set this should have even higher precedence.
+  PrefService* prefs = g_browser_process->local_state();
+  if (prefs && prefs->IsManagedPreference(prefs::kDiskCacheDir))
+    *cache_path = prefs->GetFilePath(prefs::kDiskCacheDir);
 
   const char* arg = kNormalContext == type ? switches::kDiskCacheSize :
                                              switches::kMediaCacheSize;
   std::string value =
       CommandLine::ForCurrentProcess()->GetSwitchValueASCII(arg);
 
   // By default we let the cache determine the right size.
   *max_size = 0;
   if (!base::StringToInt(value, max_size)) {
     *max_size = 0;
@@ skipping 1422 matching lines @@
   return pref_proxy_config_tracker_;
 }
 
 prerender::PrerenderManager* ProfileImpl::GetPrerenderManager() {
   if (!prerender::PrerenderManager::IsPrerenderingPossible())
     return NULL;
   if (!prerender_manager_.get())
     prerender_manager_.reset(new prerender::PrerenderManager(this));
   return prerender_manager_.get();
 }