Cleanup: Use base namespace in printing/.

printing/printing_context_win.cc

Index: printing/printing_context_win.cc
===================================================================
--- printing/printing_context_win.cc	(revision 224775)
+++ printing/printing_context_win.cc	(working copy)
@@ -319,7 +319,7 @@
   bool is_cloud_dialog;
   int copies;
   int duplex_mode;
-  string16 device_name;
+  base::string16 device_name;
 
   if (!job_settings.GetBoolean(kSettingLandscape, &landscape) ||
       !job_settings.GetBoolean(kSettingCollate, &collate) ||
@@ -456,7 +456,7 @@
 }
 
 PrintingContext::Result PrintingContextWin::NewDocument(
-    const string16& document_name) {
+    const base::string16& document_name) {
   DCHECK(!in_print_job_);
   if (!context_)
     return OnError();