Move WriteFile and WriteFileDescriptor from file_util to base namespace.

components/browser_context_keyed_service/browser_context_dependency_manager.cc

Index: components/browser_context_keyed_service/browser_context_dependency_manager.cc
diff --git a/components/browser_context_keyed_service/browser_context_dependency_manager.cc b/components/browser_context_keyed_service/browser_context_dependency_manager.cc
index bd45e7a8cd5837baddabd236db0edcae0524faeb..62fceb44dccafe5e4d3babdcefa5c12322660dc3 100644
--- a/components/browser_context_keyed_service/browser_context_dependency_manager.cc
+++ b/components/browser_context_keyed_service/browser_context_dependency_manager.cc
@@ -174,7 +174,7 @@ void BrowserContextDependencyManager::DumpBrowserContextDependencies(
     std::string contents = dependency_graph_.DumpAsGraphviz(
         "BrowserContext",
         base::Bind(&BrowserContextKeyedBaseFactoryGetNodeName));
-    file_util::WriteFile(dot_file, contents.c_str(), contents.size());
+    base::WriteFile(dot_file, contents.c_str(), contents.size());
   }
 }
 #endif  // NDEBUG