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

chrome/browser/policy/configuration_policy_pref_store.cc

Index: chrome/browser/policy/configuration_policy_pref_store.cc
diff --git a/chrome/browser/policy/configuration_policy_pref_store.cc b/chrome/browser/policy/configuration_policy_pref_store.cc
index 96dfb2eec67b6087cb60694e2dac4ec0f381c36a..7edb5436876bcc8741ff473ac6868aeed07cf3e6 100644
--- a/chrome/browser/policy/configuration_policy_pref_store.cc
+++ b/chrome/browser/policy/configuration_policy_pref_store.cc
@@ -92,6 +92,11 @@ class ConfigurationPolicyPrefKeeper
   // ownership of |value| in the case that the policy is recognized.
   bool ApplyDownloadDirPolicy(ConfigurationPolicyType policy, Value* value);
 
+  // Processes disk cache directory policy. Returns true if the specified policy
+  // is the right one. ApplyDiskCacheDirPolicy assumes the
+  // ownership of |value| in the case that the policy is recognized.
+  bool ApplyDiskCacheDirPolicy(ConfigurationPolicyType policy, Value* value);
+
   // Processes file-selection dialogs policy. Returns true if the specified
   // policy is the file-selection dialogs policy.
   // ApplyFileSelectionDialogsPolicy assumes the ownership of |value| in the
@@ -336,6 +341,9 @@ void ConfigurationPolicyPrefKeeper::Apply(ConfigurationPolicyType policy,
   if (ApplyDownloadDirPolicy(policy, value))
     return;
 
+  if (ApplyDiskCacheDirPolicy(policy, value))
+    return;
+
   if (ApplyFileSelectionDialogsPolicy(policy, value))
     return;
 
@@ -447,6 +455,26 @@ bool ConfigurationPolicyPrefKeeper::ApplyDownloadDirPolicy(
   return false;
 }
 
+bool ConfigurationPolicyPrefKeeper::ApplyDiskCacheDirPolicy(
+    ConfigurationPolicyType policy,
+    Value* value) {
+  // Replace the policy string which might contain some user variables to an
+  // expanded string.
+  if (policy == kPolicyDiskCacheDir) {
+    FilePath::StringType string_value;
+    bool result = value->GetAsString(&string_value);
+    DCHECK(result);
+    FilePath::StringType expanded_value =
+        policy::path_parser::ExpandPathVariables(string_value);
+    prefs_.SetValue(prefs::kDiskCacheDir,
+                    Value::CreateStringValue(expanded_value));
+    delete value;
+    return true;
+  }
+  // We are not interested in this policy.
+  return false;
+}
+
 bool ConfigurationPolicyPrefKeeper::ApplyFileSelectionDialogsPolicy(
     ConfigurationPolicyType policy,
     Value* value) {
@@ -1001,6 +1029,8 @@ ConfigurationPolicyPrefStore::GetChromePolicyDefinitionList() {
       key::kEditBookmarksEnabled },
     { kPolicyAllowFileSelectionDialogs, Value::TYPE_BOOLEAN,
       key::kAllowFileSelectionDialogs },
+    { kPolicyDiskCacheDir, Value::TYPE_STRING,
+      key::kDiskCacheDir },
 
 #if defined(OS_CHROMEOS)
     { kPolicyChromeOsLockOnIdleSuspend, Value::TYPE_BOOLEAN,