Move small c/b/extensions classes into extensions namespace no.2

chrome/browser/extensions/api/file_system/file_system_apitest.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 "base/file_util.h"
 #include "base/path_service.h"
 #include "chrome/browser/extensions/api/file_system/file_system_api.h"
 #include "chrome/browser/extensions/platform_app_browsertest_util.h"
 
 using extensions::FileSystemChooseFileFunction;
 
-class FileSystemApiTest : public PlatformAppBrowserTest {
+class FileSystemApiTest : public extensions::PlatformAppBrowserTest {
  public:
   virtual void SetUpCommandLine(CommandLine* command_line) OVERRIDE {
-    PlatformAppBrowserTest::SetUpCommandLine(command_line);
+    extensions::PlatformAppBrowserTest::SetUpCommandLine(command_line);
     test_root_folder_ = test_data_dir_.AppendASCII("api_test")
         .AppendASCII("file_system");
   }
 
   virtual void TearDown() OVERRIDE {
     FileSystemChooseFileFunction::StopSkippingPickerForTest();
-    PlatformAppBrowserTest::TearDown();
+    extensions::PlatformAppBrowserTest::TearDown();
   };
 
  protected:
   FilePath TempFilePath(const std::string& destination_name, bool copy_gold) {
     if (!temp_dir_.CreateUniqueTempDir()) {
       ADD_FAILURE() << "CreateUniqueTempDir failed";
       return FilePath();
     }
     FilePath destination = temp_dir_.path().AppendASCII(destination_name);
     if (copy_gold) {
@@ skipping 162 matching lines @@
 }
 
 IN_PROC_BROWSER_TEST_F(FileSystemApiTest, FileSystemApiIsWritableTest) {
   FilePath test_file = TempFilePath("writable.txt", true);
   ASSERT_FALSE(test_file.empty());
   FileSystemChooseFileFunction::SkipPickerAndAlwaysSelectPathForTest(
       &test_file);
   ASSERT_TRUE(RunPlatformAppTest(
       "api_test/file_system/is_writable_file_entry")) << message_;
 }