Revert "Trigger exception debug event for promises at the throw site."

src/promise.js

Index: src/promise.js
diff --git a/src/promise.js b/src/promise.js
index 3c8ac676540a2a3e5a3ffe87b78fb91fbbe2040d..60c836c9e6de63c087a318a45dfb181c19e7d217 100644
--- a/src/promise.js
+++ b/src/promise.js
@@ -35,13 +35,10 @@ function Promise(resolver) {
     throw MakeTypeError('resolver_not_a_function', [resolver]);
   var promise = PromiseInit(this);
   try {
-    %DebugPromiseHandlePrologue(function() { return promise });
     resolver(function(x) { PromiseResolve(promise, x) },
              function(r) { PromiseReject(promise, r) });
   } catch (e) {
     PromiseReject(promise, e);
-  } finally {
-    %DebugPromiseHandleEpilogue();
   }
 }
 
@@ -164,11 +161,6 @@ function PromiseEnqueue(value, tasks) {
 
 function PromiseHandle(value, handler, deferred) {
   try {
-    %DebugPromiseHandlePrologue(
-        function() {
-          var queue = GET_PRIVATE(deferred.promise, promiseOnReject);
-          return (queue && queue.length == 0) ? deferred.promise : UNDEFINED;
-        });
     var result = handler(value);
     if (result === deferred.promise)
       throw MakeTypeError('promise_cyclic', [result]);
@@ -177,13 +169,21 @@ function PromiseHandle(value, handler, deferred) {
     else
       deferred.resolve(result);
   } catch (exception) {
+    var uncaught = false;
+    var reject_queue = GET_PRIVATE(deferred.promise, promiseOnReject);
+    if (reject_queue && reject_queue.length == 0) {
+      // The deferred promise may get a reject handler attached later.
+      // For now, we consider the exception to be (for the moment) uncaught.
+      uncaught = true;
+    }
     try {
-      %DebugPromiseHandleEpilogue();  // Match the previous prologue.
-      %DebugPromiseHandlePrologue(function() { return deferred.promise });
       deferred.reject(exception);
-    } catch (e) { }
-  } finally {
-    %DebugPromiseHandleEpilogue();
+    } catch (e) {
+      // The reject handler can only throw for a custom deferred promise.
+      // We consider the original exception to be uncaught.
+      uncaught = true;
+    }
+    if (uncaught) %DebugPendingExceptionInPromise(exception, deferred.promise);
   }
 }
 
@@ -321,6 +321,14 @@ function GetPromiseStatus(promise) {
   return GET_PRIVATE(promise, promiseStatus);
 }
 
+function GetPromiseOnResolve(promise) {
+  return GET_PRIVATE(promise, promiseOnResolve);
+}
+
+function GetPromiseOnReject(promise) {
+  return GET_PRIVATE(promise, promiseOnReject);
+}
+
 function GetPromiseValue(promise) {
   return GET_PRIVATE(promise, promiseValue);
 }