Have /src files use header directly.

BUG=skia:

Review URL: https://codereview.chromium.org/1373253003
diff --git a/src/core/SkAAClip.cpp b/src/core/SkAAClip.cpp
index a54f0ff..bbd1f55 100644
--- a/src/core/SkAAClip.cpp
+++ b/src/core/SkAAClip.cpp
@@ -7,7 +7,7 @@
  */
 
 #include "SkAAClip.h"
-#include "../private/SkAtomics.h"
+#include "SkAtomics.h"
 #include "SkBlitter.h"
 #include "SkColorPriv.h"
 #include "SkPath.h"