Fixed shared Windows build in Chrome when building MediaPipe.

The MediaPipe library calls absl::SleepFor() but that causes linker errors in Chrome's (non-production) shared library build because AbslInternalSleepFor isn't exported.

PiperOrigin-RevId: 555699667
Change-Id: I95033857ec13ed72ff2a80001878b5e35bbeee91

absl/time/clock.h

@@ -22,6 +22,7 @@
 #ifndef ABSL_TIME_CLOCK_H_
 #define ABSL_TIME_CLOCK_H_
 
+#include "absl/base/config.h"
 #include "absl/base/macros.h"
 #include "absl/time/time.h"
 
@@ -64,7 +65,8 @@ ABSL_NAMESPACE_END
 // By changing our extension points to be extern "C", we dodge this
 // check.
 extern "C" {
-void ABSL_INTERNAL_C_SYMBOL(AbslInternalSleepFor)(absl::Duration duration);
+ABSL_DLL void ABSL_INTERNAL_C_SYMBOL(AbslInternalSleepFor)(
+    absl::Duration duration);
 }  // extern "C"
 
 inline void absl::SleepFor(absl::Duration duration) {