Trigger debug event on not yet caught exception in promises.

src/promise.js

Index: src/promise.js
diff --git a/src/promise.js b/src/promise.js
index 27890a7626b37d12af837e73627617d6a94da4f2..cdde4b35076ddc94eef399961703aa2b3e84d6dd 100644
--- a/src/promise.js
+++ b/src/promise.js
@@ -192,8 +192,14 @@ function PromiseHandle(value, handler, deferred) {
     else
       deferred.resolve(result);
   } catch(e) {
-    // TODO(rossberg): perhaps log uncaught exceptions below.
-    try { deferred.reject(e) } catch(e) {}
+    if (GET_PRIVATE(promise, promiseOnReject).length == 0) {
+      // There is no reject handler defined (yet).  The debugger should know.
+      %DebugPendingExceptionInPromise(e, promise);
+    }
+    try { deferred.reject(e) } catch(e) {
+      // Reject handler threw (must be a custom one).

[rossberg, 2014/04/24 07:27:36]

"must have been"

+      %DebugPendingExceptionInPromise(e, promise);
+    }
   }
 }