Add explicit base to FilePath.

content/shell/shell_render_process_observer.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 "content/shell/shell_render_process_observer.h"
 
 #include "base/command_line.h"
 #include "content/public/renderer/render_view.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/public/test/layouttest_support.h"
@@ skipping 87 matching lines @@
 void ShellRenderProcessObserver::OnResetAll() {
   if (main_render_view_) {
     main_test_runner_->Reset();
     WebTestingSupport::resetInternalsObject(
         main_render_view_->GetWebView()->mainFrame());
   }
   WebKitTestRunnerBindings::Reset();
 }
 
 void ShellRenderProcessObserver::OnSetWebKitSourceDir(
-    const FilePath& webkit_source_dir) {
+    const base::FilePath& webkit_source_dir) {
   webkit_source_dir_ = webkit_source_dir;
 }
 
 }  // namespace content