[SAB] Fix crash in Atomics.wake w/ infinite count.

src/futex-emulation.h

Index: src/futex-emulation.h
diff --git a/src/futex-emulation.h b/src/futex-emulation.h
index f1f3655dc74f49f26331840e4fffeeb971ee289d..801198fab8aa642414c96e271bfaa3b7a2bec345 100644
--- a/src/futex-emulation.h
+++ b/src/futex-emulation.h
@@ -82,6 +82,9 @@ class FutexWaitList {
 
 class FutexEmulation : public AllStatic {
  public:
+  // Pass to Wake() to wake all waiters.
+  static const uint32_t kWakeAll = UINT32_MAX;
+
   // Check that array_buffer[addr] == value, and return "not-equal" if not. If
   // they are equal, block execution on |isolate|'s thread until woken via
   // |Wake|, or when the time given in |rel_timeout_ms| elapses. Note that
@@ -92,10 +95,11 @@ class FutexEmulation : public AllStatic {
                       size_t addr, int32_t value, double rel_timeout_ms);
 
   // Wake |num_waiters_to_wake| threads that are waiting on the given |addr|.
-  // The rest of the waiters will continue to wait. The return value is the
-  // number of woken waiters.
+  // |num_waiters_to_wake| can be kWakeAll, in which case all waiters are
+  // woken. The rest of the waiters will continue to wait. The return value is
+  // the number of woken waiters.
   static Object* Wake(Isolate* isolate, Handle<JSArrayBuffer> array_buffer,
-                      size_t addr, int num_waiters_to_wake);
+                      size_t addr, uint32_t num_waiters_to_wake);
 
   // Return the number of threads waiting on |addr|. Should only be used for
   // testing.