Check for import from previous script.

Source/bindings/dart/DartApplicationLoader.cpp

 // Copyright (c) 2009, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 162 matching lines @@
         // Create a page-level library if necessary.
         Dart_Handle script = Dart_RootLibrary();
         if (Dart_IsNull(script)) {
             String scriptUrl = m_originDocument->url().string() + "$script";
             script = Dart_LoadScript(DartUtilities::stringToDartString(scriptUrl), Dart_NewStringFromCString(""), 0, 0);
             if (Dart_IsError(script))
                 DartUtilities::reportProblem(m_originDocument, script, scriptUrl);
         }
         ASSERT(!Dart_IsNull(script));
 
-        // FIXME(dartbug.com/13460): We need to record the lineOffset and columnOffset.
-        Dart_Handle library = Dart_LoadLibrary(DartUtilities::stringToDartString(url), dartSource);
-        if (Dart_IsError(library))
-            DartUtilities::reportProblem(m_originDocument, library, m_libraryUrl);
+        Dart_Handle libraryUrlHandle = DartUtilities::stringToDartString(url);
+        // Test if a previous script already loaded this library.
+        Dart_Handle library = Dart_LookupLibrary(libraryUrlHandle);
+        if (Dart_IsError(library)) {
+            // FIXME(dartbug.com/13460): We need to record the lineOffset and columnOffset.
+            library = Dart_LoadLibrary(libraryUrlHandle, dartSource);
+            if (Dart_IsError(library))
+                DartUtilities::reportProblem(m_originDocument, library, m_libraryUrl);
+        }
 
         Dart_Handle result = Dart_LibraryImportLibrary(script, library, Dart_Null());
         if (Dart_IsError(result))
             DartUtilities::reportProblem(m_originDocument, result, m_libraryUrl);
     } else {
         // This is a background isolate. Load as a top-level script.
         Dart_Handle script = Dart_LoadScript(DartUtilities::stringToDartString(url), dartSource, lineOffset, 0);
         if (Dart_IsError(script))
             DartUtilities::reportProblem(m_originDocument, script, m_libraryUrl);
     }
@@ skipping 85 matching lines @@
     // FIXME: try to dig out line number, -1 for now.
     if (failedUrl.startsWith(String("dart:"))) {
         m_originDocument->logExceptionToConsole(String("The built-in library '") + failedUrl + String("' is not available on Dartium."), m_libraryUrl, -1, 0, 0);
     } else {
         m_originDocument->logExceptionToConsole(String("Failed to load a file ") + failedUrl, m_libraryUrl, -1, 0, 0);
     }
     m_errorEventDispatcher->dispatchErrorEvent();
 }
 
 }