Improve Observatory debugger behaviour when an isolate exits with unhandled exceptions

runtime/vm/isolate.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/isolate.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/assert.h"
 #include "platform/text_buffer.h"
@@ skipping 40 matching lines @@
 DECLARE_FLAG(bool, print_metrics);
 DECLARE_FLAG(bool, timing);
 DECLARE_FLAG(bool, trace_service);
 
 DEFINE_FLAG(bool, trace_isolates, false,
             "Trace isolate creation and shut down.");
 DEFINE_FLAG(bool, pause_isolates_on_start, false,
             "Pause isolates before starting.");
 DEFINE_FLAG(bool, pause_isolates_on_exit, false,
             "Pause isolates exiting.");
+DEFINE_FLAG(bool, pause_isolates_on_unhandled_exceptions, false,
+            "Pause isolates on unhandled exceptions.");
+
 DEFINE_FLAG(bool, break_at_isolate_spawn, false,
             "Insert a one-time breakpoint at the entrypoint for all spawned "
             "isolates");
 
 DEFINE_FLAG(int, new_gen_semi_max_size, (kWordSize <= 4) ? 16 : 32,
             "Max size of new gen semi space in MB");
 DEFINE_FLAG(int, old_gen_heap_size, 0,
             "Max size of old gen heap size in MB, or 0 for unlimited,"
             "e.g: --old_gen_heap_size=1024 allows up to 1024MB old gen heap");
 DEFINE_FLAG(int, external_max_size, (kWordSize <= 4) ? 512 : 1024,
@@ skipping 992 matching lines @@
   if (is_runnable() == true) {
     return false;  // Already runnable.
   }
   // Set the isolate as runnable and if we are being spawned schedule
   // isolate on thread pool for execution.
   ASSERT(object_store()->root_library() != Library::null());
   set_is_runnable(true);
   if (!ServiceIsolate::IsServiceIsolate(this)) {
     message_handler()->set_pause_on_start(FLAG_pause_isolates_on_start);
     message_handler()->set_pause_on_exit(FLAG_pause_isolates_on_exit);
+    if (FLAG_pause_isolates_on_unhandled_exceptions) {
+      debugger()->SetExceptionPauseInfo(kPauseOnUnhandledExceptions);
+    }
   }
   IsolateSpawnState* state = spawn_state();
   if (state != NULL) {
     ASSERT(this == state->isolate());
     Run();
   }
   TimelineStream* stream = GetIsolateStream();
   ASSERT(stream != NULL);
   TimelineEvent* event = stream->StartEvent();
   if (event != NULL) {
@@ skipping 1470 matching lines @@
 void IsolateSpawnState::DecrementSpawnCount() {
   ASSERT(spawn_count_monitor_ != NULL);
   ASSERT(spawn_count_ != NULL);
   MonitorLocker ml(spawn_count_monitor_);
   ASSERT(*spawn_count_ > 0);
   *spawn_count_ = *spawn_count_ - 1;
   ml.Notify();
 }
 
 }  // namespace dart