Add mechanism to postpone interrupts selectively.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index 9bffca25a2ddedf955f3cb4e4642a0b4487504bd..af237524101c133d2034aad9273b36f9a7e98c15 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2371,4 +2371,15 @@ bool StackLimitCheck::JsHasOverflowed() const {
 }
 
 
+bool PostponeInterruptsScope::Intercept(StackGuard::InterruptFlag flag) {
+  // First check whether the previous scope intercepts.
+  if (prev_ && prev_->Intercept(flag)) return true;
+  // Then check whether this scope intercepts.
+  if ((flag & intercept_mask_)) {
+    intercepted_flags_ |= flag;
+    return true;
+  }
+  return false;
+}
+
 } }  // namespace v8::internal