Suppress flaky TSAN TLS false positive.

src/common/angleutils.h

@@ -319,6 +319,13 @@ inline bool IsLittleEndian()
 #    define ANGLE_NO_SANITIZE_MEMORY
 #endif
 
+// Similar to the above, but for thread sanitization.
+#ifdef __clang__
+#    define ANGLE_NO_SANITIZE_THREAD __attribute__((no_sanitize_thread))
+#else
+#    define ANGLE_NO_SANITIZE_THREAD
+#endif
+
 // The below inlining code lifted from V8.
 #if defined(__clang__) || (defined(__GNUC__) && defined(__has_attribute))
 #    define ANGLE_HAS_ATTRIBUTE_ALWAYS_INLINE (__has_attribute(always_inline))

src/libGLESv2/global_state.cpp

@@ -88,7 +88,8 @@ void SetGlobalLastContext(gl::Context *context)
 }
 
 // This function causes an MSAN false positive, which is muted. See https://crbug.com/1211047
-ANGLE_NO_SANITIZE_MEMORY Thread *GetCurrentThread()
+// It also causes a flaky false positive in TSAN. http://crbug.com/1223970
+ANGLE_NO_SANITIZE_MEMORY ANGLE_NO_SANITIZE_THREAD Thread *GetCurrentThread()
 {
     Thread *current = gCurrentThread;
     return (current ? current : AllocateCurrentThread());