Hide some SyzyASan specific code behind an '#if defined(COMPILER_MSVC)'.

base/debug/asan_invalid_access.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Defines some functions that intentionally do an invalid memory access in
 // order to trigger an AddressSanitizer (ASan) error report.
 
 #ifndef BASE_DEBUG_ASAN_INVALID_ACCESS_H_
 #define BASE_DEBUG_ASAN_INVALID_ACCESS_H_
 
@@ skipping 11 matching lines @@
 // Generates an heap buffer underflow.
 BASE_EXPORT NOINLINE void AsanHeapUnderflow();
 
 // Generates an use after free.
 BASE_EXPORT NOINLINE void AsanHeapUseAfterFree();
 
 #endif  // ADDRESS_SANITIZER || SYZYASAN
 
 // The "corrupt-block" and "corrupt-heap" classes of bugs is specific to
 // SyzyASan.
-#if defined(SYZYASAN)
+#if defined(SYZYASAN) && defined(COMPILER_MSVC)
 
 // Corrupts a memory block and makes sure that the corruption gets detected when
 // we try to free this block.
 BASE_EXPORT NOINLINE void AsanCorruptHeapBlock();
 
 // Corrupts the heap and makes sure that the corruption gets detected when a
 // crash occur.
 BASE_EXPORT NOINLINE void AsanCorruptHeap();
 
-#endif  // SYZYASAN
+#endif  // SYZYASAN && COMPILER_MSVC
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_ASAN_INVALID_ACCESS_H_