Handles path absence instead of CHECKing.

chrome/browser/extensions/external_pref_extension_loader.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/extensions/external_pref_extension_loader.h"
 
 #include "app/app_paths.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
@@ skipping 42 matching lines @@
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       NewRunnableMethod(
           this,
           &ExternalPrefExtensionLoader::LoadOnFileThread));
 }
 
 void ExternalPrefExtensionLoader::LoadOnFileThread() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 
-  CHECK(PathService::Get(base_path_key_, &base_path_));
+  scoped_ptr<DictionaryValue> prefs;
 
-  FilePath json_file;
-  json_file = base_path_.Append(FILE_PATH_LITERAL("external_extensions.json"));
+  if (PathService::Get(base_path_key_, &base_path_)) {
+    FilePath json_file;
+    json_file =
+        base_path_.Append(FILE_PATH_LITERAL("external_extensions.json"));
 
-  scoped_ptr<DictionaryValue> prefs;
-  if (file_util::PathExists(json_file)) {
-    JSONFileValueSerializer serializer(json_file);
-    prefs.reset(ExtractPrefs(&serializer));
-  } else {
+    if (file_util::PathExists(json_file)) {
+      JSONFileValueSerializer serializer(json_file);
+      prefs.reset(ExtractPrefs(&serializer));
+    }
+  }
+
+  if (!prefs.get())
     prefs.reset(new DictionaryValue());
-  }
 
   prefs_.reset(prefs.release());
   BrowserThread::PostTask(
        BrowserThread::UI, FROM_HERE,
        NewRunnableMethod(
            this,
            &ExternalPrefExtensionLoader::LoadFinished));
 }
 
 ExternalTestingExtensionLoader::ExternalTestingExtensionLoader(
     const std::string& json_data,
     const FilePath& fake_base_path)
     : fake_base_path_(fake_base_path) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   JSONStringValueSerializer serializer(json_data);
   testing_prefs_.reset(ExtractPrefs(&serializer));
 }
 
 void ExternalTestingExtensionLoader::StartLoading() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   prefs_.reset(testing_prefs_->DeepCopy());
   LoadFinished();
 }
 
 const FilePath ExternalTestingExtensionLoader::GetBaseCrxFilePath() {
   return fake_base_path_;
 }