Migrate --expose_core_impl flag from DartRunner to DartCompiler.

compiler/java/com/google/dart/runner/DartRunner.java

Index: compiler/java/com/google/dart/runner/DartRunner.java
diff --git a/compiler/java/com/google/dart/runner/DartRunner.java b/compiler/java/com/google/dart/runner/DartRunner.java
index 882ecde5de6e8b9e801662122acddba97e719afb..cabe6214126772afdd09707f1e2c720d71106dbd 100644
--- a/compiler/java/com/google/dart/runner/DartRunner.java
+++ b/compiler/java/com/google/dart/runner/DartRunner.java
@@ -16,7 +16,6 @@ import com.google.dart.compiler.DartArtifactProvider;
 import com.google.dart.compiler.DartCompilationError;
 import com.google.dart.compiler.DartCompiler;
 import com.google.dart.compiler.DartCompilerListener;
-import com.google.dart.compiler.DartSource;
 import com.google.dart.compiler.DefaultCompilerConfiguration;
 import com.google.dart.compiler.DefaultDartCompilerListener;
 import com.google.dart.compiler.DefaultErrorFormatter;
@@ -125,13 +124,6 @@ public class DartRunner {
 
     LibrarySource app = new UrlLibrarySource(new File(script));
 
-    if (options.shouldExposeCoreImpl()) {
-      imports = new ArrayList<LibrarySource>(imports);
-      // use a place-holder LibrarySource instance, to be replaced when embedded
-      // in the compiler, where the dart uri can be resolved.
-      imports.add(new NamedPlaceHolderLibrarySource("dart:coreimpl"));
-    }
-
     File outFile =  options.getOutputFilename();
 
     DefaultDartCompilerListener listener = new DefaultDartCompilerListener() {
@@ -202,49 +194,6 @@ public class DartRunner {
     throw new RunnerError(usage.toString());
   }
 
-  private static class NamedPlaceHolderLibrarySource implements LibrarySource {
-    private final String name;
-
-    public NamedPlaceHolderLibrarySource(String name) {
-      this.name = name;
-    }
-
-    @Override
-    public boolean exists() {
-      throw new AssertionError();
-    }
-
-    @Override
-    public long getLastModified() {
-      throw new AssertionError();
-    }
-
-    @Override
-    public String getName() {
-      return name;
-    }
-
-    @Override
-    public Reader getSourceReader() {
-      throw new AssertionError();
-    }
-
-    @Override
-    public URI getUri() {
-      throw new AssertionError();
-    }
-
-    @Override
-    public LibrarySource getImportFor(String relPath) {
-      throw new AssertionError();
-    }
-
-    @Override
-    public DartSource getSourceFor(String relPath) {
-      throw new AssertionError();
-    }
-  }
-
   private static class RunnerDartArtifactProvider extends DartArtifactProvider {
     private final Map<String, StringWriter> artifacts = new ConcurrentHashMap<String, StringWriter>();