Build fix for previous c16 change

Build fix for previous c16 change

c16memcmp, et al. must appear at top for inline definitions of
string16_char_traits when WCHAR_T_IS_UTF32.

TBR=mark@chromium.org

Committed: https://chromium.googlesource.com/chromium/mini_chromium/+/2ef83a609517f284096f7e8296b0915d634c3ca7

[scottmg, 2014-12-16 00:44:59]

(landing as build fix)

[scottmg, 2014-12-16 00:45:23]

Committed patchset #1 (id:1) manually as
2ef83a609517f284096f7e8296b0915d634c3ca7 (presubmit successful).

[Mark Mentovai, 2014-12-16 02:18:29]

https://codereview.chromium.org/809563003/diff/1/base/strings/string16.h
File base/strings/string16.h (right):

https://codereview.chromium.org/809563003/diff/1/base/strings/string16.h#newc...
base/strings/string16.h:35: namespace base {
This is all getting a bit sloppy. How about making it so that we start with
common stuff, then we have an #ifdef section that defines things that are common
to both #ifdefs but with different implementations. At the end, we can stick
stuff specific to one #ifdef or another.

Like:

namespace base {

int c16memcmp(…);
// other declarations

#if defined(WCHAR_T_IS_UTF16)

typedef wchar_t char16;
// other typedefs

#elif defined(WCHAR_T_IS_UTF32)

typedef uint16_t char16;

struct string16_char_traits {
  // blah blah blah
};

typedef … string16;

#endif

}  // namespace base

#if defined(WCHAR_T_IS_UTF32)

// things specific to WCHAR_T_IS_UTF32 go here
// like operator<< and and extern template class

#endif

[scottmg, 2014-12-16 17:32:23]

https://codereview.chromium.org/809563003/diff/1/base/strings/string16.h
File base/strings/string16.h (right):

https://codereview.chromium.org/809563003/diff/1/base/strings/string16.h#newc...
base/strings/string16.h:35: namespace base {
On 2014/12/16 02:18:29, Mark Mentovai wrote:
> This is all getting a bit sloppy. How about making it so that we start with
> common stuff, then we have an #ifdef section that defines things that are
common
> to both #ifdefs but with different implementations. At the end, we can stick
> stuff specific to one #ifdef or another.

Yeah, it's a bit messy. The common can't go at the top because it requires the
typedef for char16, but I think https://codereview.chromium.org/812553004 mostly
follows your suggestion in reducing the number of namespace open/closes.

> 
> Like:
> 
> namespace base {
> 
> int c16memcmp(…);
> // other declarations
> 
> #if defined(WCHAR_T_IS_UTF16)
> 
> typedef wchar_t char16;
> // other typedefs
> 
> #elif defined(WCHAR_T_IS_UTF32)
> 
> typedef uint16_t char16;
> 
> struct string16_char_traits {
>   // blah blah blah
> };
> 
> typedef … string16;
> 
> #endif
> 
> }  // namespace base
> 
> #if defined(WCHAR_T_IS_UTF32)
> 
> // things specific to WCHAR_T_IS_UTF32 go here
> // like operator<< and and extern template class
> 
> #endif

[Mark Mentovai, 2014-12-16 18:34:35]

LGTM with followups from https://codereview.chromium.org/812553004.