Clean up a few includes, introduce iwyu.

src/ports/SkDebug_stdio.cpp

-
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
-
-#include "SkTypes.h"
-
 #include <stdarg.h>

[reed1, 2015/06/24 23:20:31]

This one seems odd -- where is the declaration for SkDebugf's signature?

[bungeman-skia, 2015/06/25 14:45:06]

You're right, iwyu actually though that we didn't want SkTypes.h here because...
it didn't think that this was actually defining anything there because this
wasn't marked as SK_API, even though SK_API is defined to nothing.

This looks like magic, but I think what happens is that it notices that the
declaration has a macro token which expands to "", and the definition must also
have one to match.

This is yet another one of those interesting cases that it points out, but the
thing it suggests is mostly an informed guess. (If it's correct though, it says
it's clean.) As a result, we do need careful scrutiny around fixing includes.

 #include <stdio.h>
 
 void SkDebugf(const char format[], ...) {
     va_list args;
     va_start(args, format);
     vfprintf(stderr, format, args);
     va_end(args);
 }