Add necessary support functions so that embedders can implemented pause on start and exit

runtime/vm/dart.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/dart.h"
 
 #include "vm/code_observers.h"
 #include "vm/cpu.h"
 #include "vm/dart_api_state.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/flags.h"
 #include "vm/freelist.h"
 #include "vm/handles.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
+#include "vm/message_handler.h"
 #include "vm/metrics.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/object_id_ring.h"
 #include "vm/port.h"
 #include "vm/profiler.h"
 #include "vm/service_isolate.h"
 #include "vm/simulator.h"
 #include "vm/snapshot.h"
 #include "vm/store_buffer.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 #include "vm/thread_interrupter.h"
 #include "vm/thread_pool.h"
 #include "vm/virtual_memory.h"
 #include "vm/zone.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, print_class_table);
 DECLARE_FLAG(bool, trace_isolates);
 DECLARE_FLAG(bool, trace_time_all);
+DECLARE_FLAG(bool, pause_isolates_on_start);
+DECLARE_FLAG(bool, pause_isolates_on_exit);
 DEFINE_FLAG(bool, keep_code, false,
             "Keep deoptimized code for profiling.");
 DEFINE_FLAG(bool, shutdown, true, "Do a clean shutdown of the VM");
 
 Isolate* Dart::vm_isolate_ = NULL;
 ThreadPool* Dart::thread_pool_ = NULL;
 DebugInfo* Dart::pprof_symbol_generator_ = NULL;
 ReadOnlyHandles* Dart::predefined_handles_ = NULL;
 const uint8_t* Dart::instructions_snapshot_buffer_ = NULL;
 
@@ skipping 332 matching lines @@
   }
 
   I->heap()->EnableGrowthControl();
   I->set_init_callback_data(data);
   Api::SetupAcquiredError(I);
   if (FLAG_print_class_table) {
     I->class_table()->Print();
   }
 
   ServiceIsolate::MaybeMakeServiceIsolate(I);
-
+  if (!ServiceIsolate::IsServiceIsolate(I)) {
+    I->message_handler()->set_should_pause_on_start(
+        FLAG_pause_isolates_on_start);
+    I->message_handler()->set_should_pause_on_exit(
+        FLAG_pause_isolates_on_exit);
+  }
   ServiceIsolate::SendIsolateStartupMessage();
   I->debugger()->NotifyIsolateCreated();
 
   // Create tag table.
   I->set_tag_table(GrowableObjectArray::Handle(GrowableObjectArray::New()));
   // Set up default UserTag.
   const UserTag& default_tag = UserTag::Handle(UserTag::DefaultTag());
   I->set_current_tag(default_tag);
 
   if (FLAG_keep_code) {
@@ skipping 53 matching lines @@
   return predefined_handles_->handles_.IsValidScopedHandle(address);
 }
 
 
 bool Dart::IsReadOnlyApiHandle(Dart_Handle handle) {
   ASSERT(predefined_handles_ != NULL);
   return predefined_handles_->api_handles_.IsValidHandle(handle);
 }
 
 }  // namespace dart