Provide a counter for thrown JavaScript errors per context

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index f50c2fad876a7c8898ce1dc56451166e73815dd6..e6e64c20e72f1cf69eeb125753567d7c58d5954d 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1019,6 +1019,11 @@ Object* Isolate::Throw(Object* exception, MessageLocation* location) {
       Handle<Object> message_obj = CreateMessage(exception_handle, location);
       thread_local_top()->pending_message_obj_ = *message_obj;
 
+      bool exception_is_uncaught = (
+        PredictExceptionCatcher() != CAUGHT_BY_JAVASCRIPT);

[Michael Starzinger, 2015/10/29 13:42:55]

Notes about PredictExceptionCatcher:

1) Calling this method is not entirely for free. It will perform a stack-walk
and lookups in handler tables.
2) It can only produce an estimate (i.e. educated guess) about whether the
exception will be caught by JavaScript or not. The question whether an exception
will be caught or not is undecidable here (i.e. at the throw-site).

[Michael Hablich, 2015/10/29 15:23:34]

I moved the whole counting into the factory which should count the right things.

+
+      if (exception_is_uncaught) context()->IncrementExceptionsThrown();

[jochen (gone - plz use gerrit), 2015/10/29 14:37:07]

use native_context()

[Michael Hablich, 2015/10/29 15:23:34]

Done.

+
       // For any exception not caught by JavaScript, even when an external
       // handler is present:
       // If the abort-on-uncaught-exception flag is specified, and if the
@@ -1026,7 +1031,7 @@ Object* Isolate::Throw(Object* exception, MessageLocation* location) {
       // or if the custom callback determined that V8 should abort, then
       // abort.
       if (FLAG_abort_on_uncaught_exception &&
-          PredictExceptionCatcher() != CAUGHT_BY_JAVASCRIPT &&
+          exception_is_uncaught &&
           (!abort_on_uncaught_exception_callback_ ||
            abort_on_uncaught_exception_callback_(
                reinterpret_cast<v8::Isolate*>(this)))) {
@@ -2855,5 +2860,6 @@ bool PostponeInterruptsScope::Intercept(StackGuard::InterruptFlag flag) {
   return false;
 }
 
+
 }  // namespace internal
 }  // namespace v8