VM: Fix snapshoting slow-down caused by 99c6a18a1bc2a4f13d8dd027a597fdca0f2d6e0c.

runtime/vm/dart_api_impl.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 "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "lib/stacktrace.h"
@@ skipping 6096 matching lines @@
   return Api::Success();
 }
 
 
 DART_EXPORT Dart_Handle
 Dart_SetFileModifiedCallback(Dart_FileModifiedCallback file_mod_callback) {
   return Api::Success();
 }
 
 
+DART_EXPORT bool Dart_IsReloading() {
+  return true;

[siva, 2017/05/23 18:48:37]

Should this be false as there is no reloading in PRODUCT mode?

[Vyacheslav Egorov (Google), 2017/05/23 20:00:48]

Yep, this was a typo.

I fixed it in the local checkout but only after I uploaded CL.

+}
+
+
 DART_EXPORT void Dart_GlobalTimelineSetRecordedStreams(int64_t stream_mask) {
   return;
 }
 
 
 DART_EXPORT void Dart_SetEmbedderTimelineCallbacks(
     Dart_EmbedderTimelineStartRecording start_recording,
     Dart_EmbedderTimelineStopRecording stop_recording) {
   return;
 }
@@ skipping 115 matching lines @@
       return Api::NewError(
           "%s expects 'file_modified_callback' to be set before it is cleared.",
           CURRENT_FUNC);
     }
   }
   IsolateReloadContext::SetFileModifiedCallback(file_modified_callback);
   return Api::Success();
 }
 
 
+DART_EXPORT bool Dart_IsReloading() {
+  Thread* thread = Thread::Current();
+  Isolate* isolate = thread->isolate();
+  CHECK_ISOLATE(isolate);
+  return isolate->IsReloading();
+}
+
+
 DART_EXPORT void Dart_GlobalTimelineSetRecordedStreams(int64_t stream_mask) {
   if (!FLAG_support_timeline) {
     return;
   }
   const bool api_enabled = (stream_mask & DART_TIMELINE_STREAM_API) != 0;
   const bool compiler_enabled =
       (stream_mask & DART_TIMELINE_STREAM_COMPILER) != 0;
   const bool dart_enabled = (stream_mask & DART_TIMELINE_STREAM_DART) != 0;
   const bool debugger_enabled =
       (stream_mask & DART_TIMELINE_STREAM_DEBUGGER) != 0;
@@ skipping 597 matching lines @@
 }
 
 
 DART_EXPORT void Dart_DumpNativeStackTrace(void* context) {
 #ifndef PRODUCT
   Profiler::DumpStackTrace(context);
 #endif
 }
 
 }  // namespace dart