Start using Dart_PropagateError in the runtime/bin directory.

runtime/bin/main.cc

 // Copyright (c) 2012, 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 <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 #include "include/dart_debugger_api.h"
@@ skipping 226 matching lines @@
                                      Dart_Handle import_map) {
   if (!Dart_IsLibrary(library)) {
     return Dart_Error("not a library");
   }
   if (!Dart_IsString8(url)) {
     return Dart_Error("url is not a string");
   }
   const char* url_string = NULL;
   Dart_Handle result = Dart_StringToCString(url, &url_string);
   if (Dart_IsError(result)) {
-    return Dart_Error("accessing url characters failed");
+    return result;
   }
   bool is_dart_scheme_url = DartUtils::IsDartSchemeURL(url_string);
   bool is_dart_extension_url = DartUtils::IsDartExtensionSchemeURL(url_string);
   if (tag == kCanonicalizeUrl) {
     // If this is a Dart Scheme URL then it is not modified as it will be
     // handled by the VM internally.
     if (is_dart_scheme_url || is_dart_extension_url) {
       return url;
     }
     // Resolve the url within the context of the library's URL.
     Dart_Handle builtin_lib = Builtin::LoadLibrary(Builtin::kBuiltinLibrary);
     Dart_Handle library_url = Dart_LibraryUrl(library);
     if (Dart_IsError(library_url)) {
-      return Dart_Error("accessing library url failed");
+      return library_url;
     }
     Dart_Handle dart_args[2];
     dart_args[0] = library_url;
     dart_args[1] = url;
     return Dart_InvokeStatic(builtin_lib,
                              Dart_NewString(""), Dart_NewString("resolveUri"),
                              2, dart_args);
   }
   if (is_dart_scheme_url) {
     ASSERT(tag == kImportTag);
@@ skipping 50 matching lines @@
   dart_args[2] = Dart_False();
 #else  // !defined(TARGET_OS_WINDOWS)
   dart_args[2] = Dart_True();
 #endif  // !defined(TARGET_OS_WINDOWS)
   Dart_Handle script_url = Dart_InvokeStatic(builtin_lib,
                                              Dart_NewString(""),
                                              Dart_NewString("resolveScriptUri"),
                                              3, dart_args);
   if (Dart_IsError(script_url)) {
     fprintf(stderr, "%s", Dart_GetError(script_url));
-    return false;
+    return script_url;
   }
   if (original_script_url == NULL) {
     const char* script_url_cstr;
     Dart_StringToCString(script_url, &script_url_cstr);
     original_script_url = strdup(script_url_cstr);
   }
   dart_args[0] = script_url;
   Dart_Handle script_path = Dart_InvokeStatic(builtin_lib,
                                               Dart_NewString(""),
                                               Dart_NewString("filePathFromUri"),
@@ skipping 258 matching lines @@
   EventHandler::Terminate();
   // Terminate process exit-code handler.
   Process::TerminateExitCodeHandler();
 
   free(const_cast<char*>(original_script_name));
   free(const_cast<char*>(original_working_directory));
   free(const_cast<char*>(original_script_url));
 
   return 0;
 }