Change UTF8ToUTF16 to accept const StringPiece&.

base/utf_string_conversions.h

Index: base/utf_string_conversions.h
diff --git a/base/utf_string_conversions.h b/base/utf_string_conversions.h
index 6c49b41148c3846c23438029d0e861f13b4609c1..b9242f60eb14e2b27a2bbc0e11d34721d0622c32 100644
--- a/base/utf_string_conversions.h
+++ b/base/utf_string_conversions.h
@@ -9,10 +9,7 @@
 #include <string>
 
 #include "base/string16.h"
-
-namespace base {
-class StringPiece;
-}
+#include "base/string_piece.h"

[Avi (use Gerrit), 2011/01/26 21:58:55]

Why? We don't need it for the declaration in this file. Anyone who includes this
file and uses UTF8ToUTF16 should include it there. See the comment starting on
line 51 in this file.

[James Su, 2011/01/26 22:13:30]

But from string_piece.h:

// Functions or methods may use const StringPiece& parameters to accept either
// a "const char*" or a "string" value that will be implicitly converted to
// a StringPiece.  The implicit conversion means that it is often appropriate
// to include this .h file in other files rather than forward-declaring
// StringPiece as would be appropriate for most other Google classes.


And I think the users of UTF8ToUTF16() shouldn't care about the existence of
StringPiece at all, it would be strange for them to include string_piece.h in
order to use UTF8ToUTF16.

 
 // These convert between UTF-8, -16, and -32 strings. They are potentially slow,
 // so avoid unnecessary conversions. The low-level versions return a boolean
@@ -31,7 +28,7 @@ bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output);
 std::wstring UTF16ToWide(const string16& utf16);
 
 bool UTF8ToUTF16(const char* src, size_t src_len, string16* output);
-string16 UTF8ToUTF16(const std::string& utf8);
+string16 UTF8ToUTF16(const base::StringPiece& utf8);
 bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output);
 std::string UTF16ToUTF8(const string16& utf16);