Detect TSAN instead of relying on #ifdef THREAD_SANITIZER.

And reindent.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2293063002

CQ_INCLUDE_TRYBOTS=master.client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-TSAN-Trybot

Review-Url: https://codereview.chromium.org/2293063002

gyp/common_conditions.gypi

@@ -464,9 +464,6 @@
             ],
             'ldflags': [ '-fsanitize=<(skia_sanitizer)' ],
             'conditions' : [
-              [ 'skia_sanitizer == "thread"', {
-                'defines': [ 'THREAD_SANITIZER' ],
-              }],
               [ 'skia_sanitizer == "memory"', {
                 'cflags': [
                     '-O1',

src/core/SkSharedMutex.cpp

@@ -11,7 +11,11 @@
 #include "SkTypes.h"
 #include "SkSemaphore.h"
 
-#if defined(THREAD_SANITIZER)
+#if !defined(__has_feature)
+    #define __has_feature(x) 0
+#endif
+
+#if __has_feature(thread_sanitizer)
 
     /* Report that a lock has been created at address "lock". */
     #define ANNOTATE_RWLOCK_CREATE(lock) \
@@ -30,8 +34,8 @@
     #define ANNOTATE_RWLOCK_RELEASED(lock, is_w) \
       AnnotateRWLockReleased(__FILE__, __LINE__, lock, is_w)
 
-#ifdef DYNAMIC_ANNOTATIONS_WANT_ATTRIBUTE_WEAK
-# ifdef __GNUC__
+    #if defined(DYNAMIC_ANNOTATIONS_WANT_ATTRIBUTE_WEAK)
+        #if defined(__GNUC__)
             #define DYNAMIC_ANNOTATIONS_ATTRIBUTE_WEAK __attribute__((weak))
         #else
             /* TODO(glider): for Windows support we may want to change this macro in order