Add base:: to string16s in win8/.

win8/metro_driver/ime/text_service.cc

Index: win8/metro_driver/ime/text_service.cc
diff --git a/win8/metro_driver/ime/text_service.cc b/win8/metro_driver/ime/text_service.cc
index 7147d201f795a941444f8e97728f173598589c72..d9015cad7486a477f4925a9dfa4e99aa32240268 100644
--- a/win8/metro_driver/ime/text_service.cc
+++ b/win8/metro_driver/ime/text_service.cc
@@ -374,7 +374,7 @@ class TextServiceImpl : public TextService,
   }
 
   virtual void OnCompositionChanged(
-      const string16& text,
+      const base::string16& text,
       int32 selection_start,
       int32 selection_end,
       const std::vector<metro_viewer::UnderlineInfo>& underlines) OVERRIDE {
@@ -386,7 +386,7 @@ class TextServiceImpl : public TextService,
                                     underlines);
   }
 
-  virtual void OnTextCommitted(const string16& text) OVERRIDE {
+  virtual void OnTextCommitted(const base::string16& text) OVERRIDE {
     if (!delegate_)
       return;
     delegate_->OnTextCommitted(text);