Add --hot-reload-test-mode flag to embedder and wire it up to test.py

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 37 matching lines @@
 #include "vm/visitor.h"
 
 
 namespace dart {
 
 DECLARE_FLAG(bool, print_metrics);
 DECLARE_FLAG(bool, timing);
 DECLARE_FLAG(bool, trace_service);
 DECLARE_FLAG(bool, trace_reload);
 DECLARE_FLAG(bool, warn_on_pause_with_no_debugger);
+DECLARE_FLAG(bool, check_reloaded);
 
 NOT_IN_PRODUCT(
 static void CheckedModeHandler(bool value) {
   FLAG_enable_asserts = value;
   FLAG_enable_type_checks = value;
 }
 
 // --enable-checked-mode and --checked both enable checked mode which is
 // equivalent to setting --enable-asserts and --enable-type-checks.
 DEFINE_FLAG_HANDLER(CheckedModeHandler,
@@ skipping 1618 matching lines @@
 
     // Wait for background finalization to finish before shutting down.
     {
       MonitorLocker ml(heap_->finalization_tasks_lock());
       while (heap_->finalization_tasks() > 0) {
         ml.Wait();
       }
     }
   }
 
+  if (FLAG_check_reloaded &&
+      !ServiceIsolate::IsServiceIsolateDescendant(this)) {
+    if (!HasAttemptedReload()) {
+      OS::PrintErr("Isolate did not reload before exiting and "

[rmacnak, 2016/07/01 20:53:22]

FATAL("...")

[Cutch, 2016/07/01 21:26:40]

Done.

+                   "--check-reloaded is enabled.\n");
+      UNREACHABLE();
+    }
+  }
+
   // Then, proceed with low-level teardown.
   LowLevelShutdown();
 
 #if defined(DEBUG)
   // No concurrent sweeper tasks should be running at this point.
   if (heap_ != NULL) {
     PageSpace* old_space = heap_->old_space();
     MonitorLocker ml(old_space->tasks_lock());
     ASSERT(old_space->tasks() == 0);
   }
@@ skipping 1110 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