Clean up a few includes, introduce iwyu.

src/ports/SkDiscardableMemory_none.cpp

Index: src/ports/SkDiscardableMemory_none.cpp
diff --git a/src/ports/SkDiscardableMemory_none.cpp b/src/ports/SkDiscardableMemory_none.cpp
index 51c3164dfa6e90ea3b29f31a29461bc23bf49bcf..57396ea9bad2be0f8b75a8adb484d7905847a535 100644
--- a/src/ports/SkDiscardableMemory_none.cpp
+++ b/src/ports/SkDiscardableMemory_none.cpp
@@ -5,8 +5,10 @@
  * found in the LICENSE file.
  */
 
+#include "SkDiscardableMemory.h"
 #include "SkDiscardableMemoryPool.h"
-#include "SkTypes.h"
+
+#include <stddef.h>

[mtklein, 2015/07/28 22:04:19]

I think I'd rather "SkTypes.h" than <stddef.h>, unless we switch everything over
to include <stdfoo.h> themselves.

[bungeman-skia, 2015/07/29 16:46:23]

I'd like to switch to <cstdfoo> directly. I assume the reason for any of the
standard headers being 'provided' by SkTypes is that in the wild west of the
past you may not actually have them, so it might need to synthesize them, or
include something else (see history of stdint for a good example). It's fine for
SkTypes to include whatever headers it needs for it's own code (which there
seems to excessive amounts of, some of it needs to be in SkTemplates.h. and that
might want to be broken up a bit too), but I'd like to minimize the amount it
purposefully exports (for example stdlib is really big).

[mtklein, 2015/07/29 18:05:02]

sgtm

 
 SkDiscardableMemory* SkDiscardableMemory::Create(size_t bytes) {
     return SkGetGlobalDiscardableMemoryPool()->create(bytes);