Revert change 7506 to check on build failure.

bin/gen_snapshot.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.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ skipping 139 matching lines @@
 static Dart_Handle LoadSnapshotCreationScript(const char* script_name) {
   Dart_Handle source = DartUtils::ReadStringFromFile(script_name);
   if (Dart_IsError(source)) {
     return source;  // source contains the error string.
   }
   Dart_Handle url = Dart_NewString(script_name);
   Dart_Handle import_map = Dart_NewList(0);
 
   return Dart_LoadScript(url,
                          source,
+                         CreateSnapshotLibraryTagHandler,
                          import_map);
 }
 
 
 static Dart_Handle BuiltinLibraryTagHandler(Dart_LibraryTag tag,
                                             Dart_Handle library,
                                             Dart_Handle url,
                                             Dart_Handle import_map) {
   if (!Dart_IsLibrary(library)) {
     return Dart_Error("not a library");
@@ skipping 99 matching lines @@
     exit(255);
   }
 
   Dart_Handle result;
   Dart_Handle library;
   Dart_EnterScope();
 
   ASSERT(snapshot_filename != NULL);
   // Load up the script before a snapshot is created.
   if (app_script_name != NULL) {
-    // Set up the library tag handler for this isolate.
-    result = Dart_SetLibraryTagHandler(CreateSnapshotLibraryTagHandler);
-    if (Dart_IsError(result)) {
-      fprintf(stderr, "%s", Dart_GetError(result));
-      Dart_ExitScope();
-      Dart_ShutdownIsolate();
-      exit(255);
-    }
     // Load the specified script.
     library = LoadSnapshotCreationScript(app_script_name);
     VerifyLoaded(library);
   } else {
-    // Set up the library tag handler for this isolate.
-    result = Dart_SetLibraryTagHandler(BuiltinLibraryTagHandler);
-    if (Dart_IsError(result)) {
-      fprintf(stderr, "%s", Dart_GetError(result));
-      Dart_ExitScope();
-      Dart_ShutdownIsolate();
-      exit(255);
-    }
+    // Load a dummy script as the script to setup the tag handler.
+    Dart_Handle empty_string = Dart_NewString("");
+    library = Dart_LoadScript(empty_string,
+                                      empty_string,
+                                      BuiltinLibraryTagHandler,
+                                      Dart_Null());
+    VerifyLoaded(library);
     // This is a generic dart snapshot which needs builtin library setup.
-    Dart_Handle library =
-        LoadGenericSnapshotCreationScript(Builtin::kBuiltinLibrary);
+    library = LoadGenericSnapshotCreationScript(Builtin::kBuiltinLibrary);
     VerifyLoaded(library);
     library = LoadGenericSnapshotCreationScript(Builtin::kIOLibrary);
     VerifyLoaded(library);
     library = LoadGenericSnapshotCreationScript(Builtin::kJsonLibrary);
     VerifyLoaded(library);
     library = LoadGenericSnapshotCreationScript(Builtin::kUriLibrary);
     VerifyLoaded(library);
     library = LoadGenericSnapshotCreationScript(Builtin::kUtfLibrary);
     VerifyLoaded(library);
   }
@@ skipping 10 matching lines @@
     exit(255);
   }
   // Now write the snapshot out to specified file and exit.
   WriteSnapshotFile(buffer, size);
   Dart_ExitScope();
 
   // Shutdown the isolate.
   Dart_ShutdownIsolate();
   return 0;
 }