[debugger] flood function for stepping on throw.

src/execution.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/execution.h"
 
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/isolate-inl.h"
@@ skipping 92 matching lines @@
   if (FLAG_verify_heap) {
     value->ObjectVerify();
   }
 #endif
 
   // Update the pending exception flag and return the value.
   bool has_exception = value->IsException();
   DCHECK(has_exception == isolate->has_pending_exception());
   if (has_exception) {
     isolate->ReportPendingMessages();
-    // Reset stepping state when script exits with uncaught exception.
-    if (isolate->debug()->is_active()) {
-      isolate->debug()->ClearStepping();
-    }
     return MaybeHandle<Object>();
   } else {
     isolate->clear_pending_message();
   }
 
   return Handle<Object>(value, isolate);
 }
 
 }  // namespace
 
@@ skipping 384 matching lines @@
 
   isolate_->counters()->stack_interrupts()->Increment();
   isolate_->counters()->runtime_profiler_ticks()->Increment();
   isolate_->runtime_profiler()->OptimizeNow();
 
   return isolate_->heap()->undefined_value();
 }
 
 }  // namespace internal
 }  // namespace v8