Convert string16 to base::string16 in content.

content/common/mac/attributed_string_coder.h

Index: content/common/mac/attributed_string_coder.h
diff --git a/content/common/mac/attributed_string_coder.h b/content/common/mac/attributed_string_coder.h
index 629beedff4ead5360ad03393435f8eb9c6d12fd9..35b3bf54a55403009bc2ff18ebc894235be96acf 100644
--- a/content/common/mac/attributed_string_coder.h
+++ b/content/common/mac/attributed_string_coder.h
@@ -62,12 +62,12 @@ class CONTENT_EXPORT AttributedStringCoder {
   // which can be serialized over IPC.
   class EncodedString {
    public:
-    explicit EncodedString(string16 string);
+    explicit EncodedString(base::string16 string);
     EncodedString();
     ~EncodedString();
 
     // Accessors:
-    string16 string() const { return string_; }
+    base::string16 string() const { return string_; }
     const std::vector<FontAttribute>& attributes() const {
       return attributes_;
     }
@@ -75,7 +75,7 @@ class CONTENT_EXPORT AttributedStringCoder {
 
    private:
     // The plain-text string.
-    string16 string_;
+    base::string16 string_;
     // The set of attributes that style |string_|.
     std::vector<FontAttribute> attributes_;
   };