[debug] use catch prediction flag for promise rejections.

test/mjsunit/es6/debug-promises/throw-with-throw-in-reject.js

 // 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.
 
 // Flags: --expose-debug-as debug --allow-natives-syntax --promise-extra
 
 // Test debug events when an exception is thrown inside a Promise, which is
 // caught by a custom promise, which throws a new exception in its reject
 // handler. We expect two Exception debug events:
 //  1) when the exception is thrown in the promise q.
 //  2) when the custom reject closure in MyPromise throws an exception.
 
 Debug = debug.Debug;
 
-var expected_events = 2;
+var expected_events = 1;
 var log = [];
 
 var p = new Promise(function(resolve, reject) {
   log.push("resolve");
   resolve();
 });
 
 function MyPromise(resolver) {
   var reject = function() {
     log.push("throw in reject");
@@ skipping 12 matching lines @@
   function() {
     log.push("throw caught");
     throw new Error("caught");  // event
   });
 
 function listener(event, exec_state, event_data, data) {
   try {
     if (event == Debug.DebugEvent.Exception) {
       expected_events--;
       assertTrue(expected_events >= 0);
-      if (expected_events == 1) {
+      if (expected_events == 0) {
         assertEquals(["resolve", "construct", "end main",
                       "throw caught"], log);
         assertEquals("caught", event_data.exception().message);
-      } else if (expected_events == 0) {
-        assertEquals("reject", event_data.exception().message);

[Dan Ehrenberg, 2016/07/21 21:07:33]

Nice fix; this really isn't a rejection.

       } else {
         assertUnreachable();
       }
       assertSame(q, event_data.promise());
       assertTrue(exec_state.frame(0).sourceLineText().indexOf('// event') > 0);
     }
   } catch (e) {
     %AbortJS(e + "\n" + e.stack);
   }
 }
@@ skipping 15 matching lines @@
       }
     } catch (e) {
       %AbortJS(e + "\n" + e.stack);
     }
   }
 
   %EnqueueMicrotask(checkResult);
 }
 
 testDone(0);