Add explicit base namespace to string16 users.

chrome/common/importer/profile_import_process_messages.h

Index: chrome/common/importer/profile_import_process_messages.h
diff --git a/chrome/common/importer/profile_import_process_messages.h b/chrome/common/importer/profile_import_process_messages.h
index 1e5bab626c78e928a77b40edfb5cf9b3047a481c..baa913eb6e38ae802c3fa749ceed107b290fc677 100644
--- a/chrome/common/importer/profile_import_process_messages.h
+++ b/chrome/common/importer/profile_import_process_messages.h
@@ -92,7 +92,7 @@ struct ParamTraits<ImporterURLRow> {
   }
   static bool Read(const Message* m, PickleIterator* iter, param_type* p) {
     GURL url;
-    string16 title;
+    base::string16 title;
     int visit_count, typed_count;
     base::Time last_visit;
     bool hidden;
@@ -300,8 +300,8 @@ IPC_MESSAGE_CONTROL1(ProfileImportProcessHostMsg_NotifyHomePageImportReady,
                      GURL  /* GURL of home page */)
 
 IPC_MESSAGE_CONTROL2(ProfileImportProcessHostMsg_NotifyBookmarksImportStart,
-                     string16  /* first folder name */,
-                     int       /* total number of bookmarks */)
+                     base::string16  /* first folder name */,
+                     int             /* total number of bookmarks */)
 
 IPC_MESSAGE_CONTROL1(ProfileImportProcessHostMsg_NotifyBookmarksImportGroup,
                      std::vector<ImportedBookmarkEntry>)