Fixed check return warnings from Coverity.

chrome/browser/policy/managed_mode_policy_provider.cc

 // Copyright (c) 2012 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/policy/managed_mode_policy_provider.h"
 
 #include "chrome/browser/policy/policy_bundle.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/json_pref_store.h"
 #include "chrome/common/chrome_constants.h"
@@ skipping 25 matching lines @@
 }
 
 ManagedModePolicyProvider::~ManagedModePolicyProvider() {
   store_->RemoveObserver(this);
 }
 
 const base::Value* ManagedModePolicyProvider::GetPolicy(
     const std::string& key) const {
   base::DictionaryValue* dict = GetCachedPolicy();
   base::Value* value = NULL;
+
+  // Returns NULL if the key doesn't exist.
   dict->GetWithoutPathExpansion(key, &value);
   return value;
 }
 
 void ManagedModePolicyProvider::SetPolicy(const std::string& key,
                                           const base::Value* value) {
   base::DictionaryValue* dict = GetCachedPolicy();
   dict->SetWithoutPathExpansion(key, value->DeepCopy());
   store_->ReportValueChanged(kPolicies);
   UpdatePolicyFromCache();
@@ skipping 39 matching lines @@
 void ManagedModePolicyProvider::UpdatePolicyFromCache() {
   scoped_ptr<PolicyBundle> policy_bundle(new PolicyBundle);
   PolicyMap* policy_map =
       &policy_bundle->Get(POLICY_DOMAIN_CHROME, std::string());
   policy_map->LoadFrom(GetCachedPolicy(),
                        POLICY_LEVEL_MANDATORY, POLICY_SCOPE_USER);
   UpdatePolicy(policy_bundle.Pass());
 }
 
 }  // namespace policy