Don't forward invalid line offsets for generated scripts to Dart_Load*.

Source/bindings/dart/DartAsyncLoader.cpp

 // Copyright (c) 2013, 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 185 matching lines @@
     }
 
     for (ScriptList::iterator i = m_scriptsToLoad.begin(); i != m_scriptsToLoad.end(); ++i) {
         RefPtr<DartScriptInfo> script = *i;
         const String& src = script->sourceAttributeValue();
         const String& url = script->url();
         if (src.isEmpty()) {
             // Inline script.
             ASSERT(!m_pendingLibraries.contains(url));
             m_pendingLibraries.add(url);
-            process(script->url(), script->scriptContent(), script->startLineNumber().zeroBasedInt());
+            intptr_t lineOffset = script->startLineNumber().zeroBasedInt();
+            // Blink gives generated script tags an invalid start line.
+            if (lineOffset < 0)
+                lineOffset = 0;
+            process(script->url(), script->scriptContent(), lineOffset);
         } else {
             // Canonicalize the src attribute url.
             String canonical = KURL(script->ownerDocument()->url(), src).string();
             // Request if we don't have the script or haven't already requested it.
             if (!m_pendingLibraries.contains(canonical)) {
                 m_pendingLibraries.add(canonical);
                 fetchScriptResource(canonical);
             }
         }
     }
@@ skipping 208 matching lines @@
     ResourcePtr<ScriptResource> scriptResource = m_loadCallback->requestScript(request);
     if (scriptResource) {
         scriptResource->addClient(new ScriptLoadedCallback(m_loadCallback->completeURL(url), this, scriptResource));
     } else {
         m_error = true;
         m_loadCallback->reportError(String("File request error"), url);
     }
 }
 
 }