rtc::Optional: Tell sanitizers that unset values aren't OK to access

webrtc/base/optional.cc

Index: webrtc/base/optional.cc
diff --git a/webrtc/base/logging_mac.mm b/webrtc/base/optional.cc
similarity index 63%
copy from webrtc/base/logging_mac.mm
copy to webrtc/base/optional.cc
index ffee3541a48245e0179670ce2b013f957bc6b88a..6bebdd5a19225fcf46424e97c95d28ccba1b800e 100644
--- a/webrtc/base/logging_mac.mm
+++ b/webrtc/base/optional.cc
@@ -8,15 +8,16 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
-#include "webrtc/base/logging.h"
+#include "webrtc/base/optional.h"
 
-#import <Foundation/Foundation.h>
+namespace rtc {
+namespace optional_internal {
 
+#if RTC_HAS_ASAN
 
-namespace rtc {
-std::string DescriptionFromOSStatus(OSStatus err) {
-  NSError* error =
-      [NSError errorWithDomain:NSOSStatusErrorDomain code:err userInfo:nil];
-  return error.description.UTF8String;
-}
+void* FunctionThatDoesNothingImpl(void* x) { return x; }
+
+#endif
+
+}  // namespace optional_internal
 }  // namespace rtc