Rename URLFetcherImpl::Core::TempFileWriter to FileWriter

URLFetcher is going to have a new method 'SaveResponseToFile'.
FileWriter is going to manage both temporary and ordinary files.

BUG=chromium-os:26971
TEST=content_unittests --gtest_filter="URLFetcher*"


Review URL: http://codereview.chromium.org/9580003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@124846 0039d316-1c4b-4281-b951-d872f2087c98

content/common/net/url_fetcher_impl.h

@@ -83,7 +83,7 @@ class CONTENT_EXPORT URLFetcherImpl : public content::URLFetcher{
   // How should the response be stored?
   enum ResponseDestinationType {
     STRING,  // Default: In a std::string
-    TEMP_FILE  // Write to a temp file
+    FILE  // Write to a file
   };
 
   // Returns the delegate.