Clean up unused stuff in atomicops_internals_{tsan,gcc}.h

src/base/atomicops_internals_tsan.h

Index: src/base/atomicops_internals_tsan.h
diff --git a/src/base/atomicops_internals_tsan.h b/src/base/atomicops_internals_tsan.h
index 363668d86d3c7b65b7656472d538aaf5ee076b7f..646e5bd4b746029ac26bf495fb589bfa6d664269 100644
--- a/src/base/atomicops_internals_tsan.h
+++ b/src/base/atomicops_internals_tsan.h
@@ -15,20 +15,6 @@ namespace base {
 #ifndef TSAN_INTERFACE_ATOMIC_H
 #define TSAN_INTERFACE_ATOMIC_H
 
-// This struct is not part of the public API of this module; clients may not
-// use it.  (However, it's exported via BASE_EXPORT because clients implicitly
-// do use it at link time by inlining these functions.)
-// Features of this x86.  Values may not be correct before main() is run,
-// but are set conservatively.
-struct AtomicOps_x86CPUFeatureStruct {
-  bool has_amd_lock_mb_bug;  // Processor has AMD memory-barrier bug; do lfence
-                             // after acquire compare-and-swap.
-  bool has_sse2;             // Processor has SSE2.
-};
-extern struct AtomicOps_x86CPUFeatureStruct
-    AtomicOps_Internalx86CPUFeatures;
-
-#define ATOMICOPS_COMPILER_BARRIER() __asm__ __volatile__("" : : : "memory")
 
 extern "C" {
 typedef char  __tsan_atomic8;
@@ -374,6 +360,4 @@ inline void MemoryBarrier() {
 }  // namespace base
 }  // namespace v8
 
-#undef ATOMICOPS_COMPILER_BARRIER
-
 #endif  // V8_BASE_ATOMICOPS_INTERNALS_TSAN_H_