Move sync code to include/, switch from using platform define to a proxy header in core/

This fixes two problems:
  1)  #include SK_SOME_DEFINE doesn't work well for all our clients.
  2)  Things in include/ are #including things in src/, which we don't like.

TBR=reed@google.com

BUG=skia:

Review URL: https://codereview.chromium.org/862983002

gyp/ports.gyp

@@ -22,10 +22,6 @@
         '../src/utils',
       ],
       'sources': [
-        '../src/ports/SkAtomics_sync.h',
-        '../src/ports/SkAtomics_win.h',
-        '../src/ports/SkMutex_pthread.h',
-        '../src/ports/SkMutex_win.h',
         '../src/ports/SkDebug_nacl.cpp',
         '../src/ports/SkDebug_stdio.cpp',
         '../src/ports/SkDebug_win.cpp',
@@ -44,8 +40,6 @@
 
         '../src/ports/SkGlobalInitialization_default.cpp',
         '../src/ports/SkMemory_malloc.cpp',
-        '../src/ports/SkMutex_pthread.h',
-        '../src/ports/SkMutex_win.h',
         '../src/ports/SkOSFile_posix.cpp',
         '../src/ports/SkOSFile_stdio.cpp',
         '../src/ports/SkOSFile_win.cpp',

gyp/tools.gyp

@@ -607,6 +607,13 @@
         ],
         'paths_to_ignore': [
           '<(skia_include_path)/gpu/gl/GrGLConfig_chrome.h',
+          '<(skia_include_path)/ports/SkAtomics_sync.h',
+          '<(skia_include_path)/ports/SkAtomics_win.h',
+          '<(skia_include_path)/ports/SkBarriers_arm.h',
+          '<(skia_include_path)/ports/SkBarriers_tsan.h',
+          '<(skia_include_path)/ports/SkBarriers_x86.h',
+          '<(skia_include_path)/ports/SkMutex_pthread.h',
+          '<(skia_include_path)/ports/SkMutex_win.h',
           '<(skia_include_path)/ports/SkTypeface_mac.h',
           '<(skia_include_path)/ports/SkTypeface_win.h',
           '<(skia_include_path)/utils/ios',

include/config/SkUserConfig.h

@@ -168,14 +168,4 @@
  */
 //#define SK_PDF_USE_PATHOPS
 
-/* Skia uses these defines as the target of include preprocessor directives.
- * The header files pointed to by these defines provide declarations and
- * possibly inline implementations of threading primitives.
- *
- * See SkThread.h for documentation on what these includes must contain.
- */
-//#define SK_ATOMICS_PLATFORM_H "SkAtomics_xxx.h"
-//#define SK_MUTEX_PLATFORM_H "SkMutex_xxx.h"
-//#define SK_BARRIERS_PLATFORM_H "SkBarriers_xxx.h"
-
 #endif

include/core/SkAtomics.h

@@ -0,0 +1,13 @@
+#ifndef SkAtomics_DEFINED
+#define SkAtomics_DEFINED
+
+// This file is not part of the public Skia API.
+#include "SkTypes.h"
+
+#if defined(_MSC_VER)
+    #include "../ports/SkAtomics_win.h"
+#else
+    #include "../ports/SkAtomics_sync.h"
+#endif
+
+#endif//SkAtomics_DEFINED

include/core/SkBarriers.h

@@ -0,0 +1,15 @@
+#ifndef SkBarriers_DEFINED
+#define SkBarriers_DEFINED
+
+// This file is not part of the public Skia API.
+#include "SkTypes.h"
+
+#if SK_HAS_COMPILER_FEATURE(thread_sanitizer)
+    #include "../ports/SkBarriers_tsan.h"
+#elif defined(SK_CPU_ARM32) || defined(SK_CPU_ARM64)
+    #include "../ports/SkBarriers_arm.h"
+#else
+    #include "../ports/SkBarriers_x86.h"
+#endif
+
+#endif//SkBarriers_DEFINED

include/core/SkMutex.h

@@ -0,0 +1,13 @@
+#ifndef SkMutex_DEFINED
+#define SkMutex_DEFINED
+
+// This file is not part of the public Skia API.
+#include "SkTypes.h"
+
+#if defined(SK_BUILD_FOR_WIN)
+    #include "../ports/SkMutex_win.h"
+#else
+    #include "../ports/SkMutex_pthread.h"
+#endif
+
+#endif//SkMutex_DEFINED

include/core/SkPostConfig.h

@@ -385,34 +385,6 @@
 
 //////////////////////////////////////////////////////////////////////
 
-#ifndef SK_ATOMICS_PLATFORM_H
-#  if defined(_MSC_VER)
-#    define SK_ATOMICS_PLATFORM_H "../../src/ports/SkAtomics_win.h"
-#  else
-#    define SK_ATOMICS_PLATFORM_H "../../src/ports/SkAtomics_sync.h"
-#  endif
-#endif
-
-#ifndef SK_MUTEX_PLATFORM_H
-#  if defined(SK_BUILD_FOR_WIN)
-#    define SK_MUTEX_PLATFORM_H "../../src/ports/SkMutex_win.h"
-#  else
-#    define SK_MUTEX_PLATFORM_H "../../src/ports/SkMutex_pthread.h"
-#  endif
-#endif
-
-#ifndef SK_BARRIERS_PLATFORM_H
-#  if SK_HAS_COMPILER_FEATURE(thread_sanitizer)
-#    define SK_BARRIERS_PLATFORM_H "../../src/ports/SkBarriers_tsan.h"
-#  elif defined(SK_CPU_ARM32) || defined(SK_CPU_ARM64)
-#    define SK_BARRIERS_PLATFORM_H "../../src/ports/SkBarriers_arm.h"
-#  else
-#    define SK_BARRIERS_PLATFORM_H "../../src/ports/SkBarriers_x86.h"
-#  endif
-#endif
-
-//////////////////////////////////////////////////////////////////////
-
 #ifndef SK_EGL
 #  if defined(SK_BUILD_FOR_ANDROID) || defined(SK_BUILD_FOR_NACL)
 #    define SK_EGL 1

include/core/SkThread.h

@@ -10,7 +10,7 @@
 
 #include "SkTypes.h"
 
-// SK_ATOMICS_PLATFORM_H must provide inline implementations for the following declarations.
+// SkAtomics.h must provide inline implementations for the following declarations.
 
 /** Atomically adds one to the int referenced by addr and returns the previous value.
  *  No additional memory barrier is required; this must act as a compiler barrier.
@@ -44,11 +44,7 @@ static void sk_membar_acquire__after_atomic_dec();
  */
 static void sk_membar_acquire__after_atomic_conditional_inc();
 
-#ifdef GOOGLE3
-    #include "SkAtomics_sync.h"
-#else
-    #include SK_ATOMICS_PLATFORM_H
-#endif
+#include "SkAtomics.h"
 
 /** Atomically adds one to the int referenced by addr iff the referenced int was not 0
  *  and returns the previous value.
@@ -65,7 +61,7 @@ template<typename INT_TYPE> static inline INT_TYPE sk_atomic_conditional_inc(INT
     return prev;
 }
 
-// SK_BARRIERS_PLATFORM_H must provide implementations for the following declarations:
+// SkBarriers.h must provide implementations for the following declarations:
 
 /** Prevent the compiler from reordering across this barrier. */
 static void sk_compiler_barrier();
@@ -82,13 +78,9 @@ template <typename T> T sk_acquire_load(T*);
  */
 template <typename T> void sk_release_store(T*, T);
 
-#ifdef GOOGLE3
-    #include "SkBarriers_x86.h"
-#else
-    #include SK_BARRIERS_PLATFORM_H
-#endif
+#include "SkBarriers.h"
 
-/** SK_MUTEX_PLATFORM_H must provide the following (or equivalent) declarations.
+/** SkMutex.h must provide the following (or equivalent) declarations.
 
 class SkBaseMutex {
 public:
@@ -106,12 +98,7 @@ public:
 #define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name = ...
 */
 
-#ifdef GOOGLE3
-    #include "SkMutex_pthread.h"
-#else
-    #include SK_MUTEX_PLATFORM_H
-#endif
-
+#include "SkMutex.h"
 
 class SkAutoMutexAcquire : SkNoncopyable {
 public:

include/core/SkThreadPriv.h

@@ -10,7 +10,7 @@
 
 #include "SkTypes.h"
 
-// SK_ATOMICS_PLATFORM_H must provide inline implementations for the following declarations.
+// SkAtomics.h must provide inline implementations for the following declarations.
 
 /** Atomic compare and set, for pointers.
  *  If *addr == before, set *addr to after.  Always returns previous value of *addr.
@@ -18,10 +18,6 @@
  */
 static void* sk_atomic_cas(void** addr, void* before, void* after);
 
-#ifdef GOOGLE3
-    #include "SkAtomics_sync.h"
-#else
-    #include SK_ATOMICS_PLATFORM_H
-#endif
+#include "SkAtomics.h"
 
 #endif//SkThreadPriv_DEFINED