Make --trace-loading great again.

runtime/bin/vmservice_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 "bin/vmservice_impl.h"
 
 #include "include/dart_api.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
@@ skipping 152 matching lines @@
   SHUTDOWN_ON_ERROR(result);
   result = Dart_FinalizeLoading(false);
   SHUTDOWN_ON_ERROR(result);
   return true;
 }
 
 
 bool VmService::Setup(const char* server_ip,
                       intptr_t server_port,
                       bool running_precompiled,
-                      bool dev_mode_server) {
+                      bool dev_mode_server,
+                      bool trace_loading) {
   Dart_Isolate isolate = Dart_CurrentIsolate();
   ASSERT(isolate != NULL);
   SetServerAddress("");
 
   Dart_Handle result;
 
   // Prepare builtin and its dependent libraries for use to resolve URIs.
   // Set up various closures, e.g: printing, timers etc.
   // Set up 'package root' for URI resolution.
   result = DartUtils::PrepareForScriptLoading(true, false);
@@ skipping 66 matching lines @@
 // Are we running on Fuchsia?
 #if defined(HOST_OS_FUCHSIA)
   Dart_Handle is_fuchsia = Dart_True();
 #else
   Dart_Handle is_fuchsia = Dart_False();
 #endif
   result =
       Dart_SetField(library, DartUtils::NewString("_isFuchsia"), is_fuchsia);
   SHUTDOWN_ON_ERROR(result);
 
+  if (trace_loading) {
+    result = Dart_SetField(library, DartUtils::NewString("_traceLoading"),
+                           Dart_True());
+    SHUTDOWN_ON_ERROR(result);
+  }
+
   // Get _getWatchSignalInternal from dart:io.
   Dart_Handle dart_io_str = Dart_NewStringFromCString(DartUtils::kIOLibURL);
   SHUTDOWN_ON_ERROR(dart_io_str);
   Dart_Handle io_lib = Dart_LookupLibrary(dart_io_str);
   SHUTDOWN_ON_ERROR(io_lib);
   Dart_Handle function_name =
       Dart_NewStringFromCString("_getWatchSignalInternal");
   SHUTDOWN_ON_ERROR(function_name);
   Dart_Handle signal_watch = Dart_Invoke(io_lib, function_name, 0, NULL);
   SHUTDOWN_ON_ERROR(signal_watch);
@@ skipping 95 matching lines @@
   Dart_Handle source = GetSource(url_string);
   if (Dart_IsError(source)) {
     return source;
   }
   return Dart_LoadSource(library, url, Dart_Null(), source, 0, 0);
 }
 
 
 }  // namespace bin
 }  // namespace dart