Fix double-printing of loading errors in gen_snapshot.

runtime/bin/gen_snapshot.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.
 
 // Generate a snapshot file after loading all the scripts specified on the
 // command line.
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 656 matching lines @@
 "                                      binary                                \n"
 "                                                                            \n"
 "    --embedder_entry_points_manifest=<file> (Precompilation or app          \n"
 "                                      snapshots) Contains embedder's entry  \n"
 "                                      points into Dart code from the C API. \n"
 "\n");
 }
 // clang-format on
 
 
-static void VerifyLoaded(Dart_Handle library) {
-  if (Dart_IsError(library)) {
-    const char* err_msg = Dart_GetError(library);
-    Log::PrintErr("Errors encountered while loading: %s\n", err_msg);
-    CHECK_RESULT(library);
-  }
-  ASSERT(Dart_IsLibrary(library));
-}
-
-
 static const char StubNativeFunctionName[] = "StubNativeFunction";
 
 
 void StubNativeFunction(Dart_NativeArguments arguments) {
   // This is a stub function for the resolver
   Dart_SetReturnValue(
       arguments, Dart_NewApiError("<EMBEDDER DID NOT SETUP NATIVE RESOLVER>"));
 }
 
 
@@ skipping 416 matching lines @@
   Dart_Handle result = Dart_SetLibraryTagHandler(Loader::LibraryTagHandler);
   if (Dart_IsError(result)) {
     Log::PrintErr("%s", Dart_GetError(result));
     Dart_ExitScope();
     Dart_ShutdownIsolate();
     exit(kErrorExitCode);
   }
   // This is a generic dart snapshot which needs builtin library setup.
   Dart_Handle library =
       LoadGenericSnapshotCreationScript(Builtin::kBuiltinLibrary);
-  VerifyLoaded(library);
+  CHECK_RESULT(library);
 }
 
 
 static void SetupForGenericSnapshotCreation() {
   SetupForUriResolution();
 
   Dart_Handle library = LoadGenericSnapshotCreationScript(Builtin::kIOLibrary);
-  VerifyLoaded(library);
+  CHECK_RESULT(library);
   Dart_Handle result = Dart_FinalizeLoading(false);
   if (Dart_IsError(result)) {
     const char* err_msg = Dart_GetError(library);
     Log::PrintErr("Errors encountered while loading: %s\n", err_msg);
     Dart_ExitScope();
     Dart_ShutdownIsolate();
     exit(kErrorExitCode);
   }
 }
 
@@ skipping 203 matching lines @@
       CHECK_RESULT(result);
     }
 
     SetupStubNativeResolversForPrecompilation(entry_points);
 
     SetupStubNativeResolvers();
 
     if (!is_kernel_file) {
       // Load the specified script.
       library = LoadSnapshotCreationScript(app_script_name);
-      VerifyLoaded(library);
+      CHECK_RESULT(library);
 
       ImportNativeEntryPointLibrariesIntoRoot(entry_points);
     }
 
     // Ensure that we mark all libraries as loaded.
     result = Dart_FinalizeLoading(false);
     CHECK_RESULT(result);
 
     if (!IsSnapshottingForPrecompilation()) {
       CreateAndWriteSnapshot();
@@ skipping 17 matching lines @@
   EventHandler::Stop();
   return 0;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   return dart::bin::main(argc, argv);
 }