Migrate --expose_core_impl flag from DartRunner to DartCompiler.

compiler/java/com/google/dart/compiler/DartCompiler.java

Index: compiler/java/com/google/dart/compiler/DartCompiler.java
diff --git a/compiler/java/com/google/dart/compiler/DartCompiler.java b/compiler/java/com/google/dart/compiler/DartCompiler.java
index e860694aaf961e36c05236ae59a13f9a269e8df0..c40658658db2cf78a2fe34b8e102f3e4c0ccb2d8 100644
--- a/compiler/java/com/google/dart/compiler/DartCompiler.java
+++ b/compiler/java/com/google/dart/compiler/DartCompiler.java
@@ -4,6 +4,7 @@
 
 package com.google.dart.compiler;
 
+import com.google.common.collect.Lists;
 import com.google.common.io.CharStreams;
 import com.google.common.io.Closeables;
 import com.google.common.io.Files;
@@ -70,6 +71,49 @@ public class DartCompiler {
   public static final String CORELIB_URL_SPEC = "dart:core";
   public static final String MAIN_ENTRY_POINT_NAME = "main";
 
+  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 Compiler {
     private final LibrarySource app;
     private final List<LibrarySource> embeddedLibraries = new ArrayList<LibrarySource>();
@@ -417,7 +461,7 @@ public class DartCompiler {
             }
           }
         }
-        
+
         if (filesHaveChanged) {
           context.setFilesHaveChanged();
         }
@@ -500,7 +544,7 @@ public class DartCompiler {
         Tracer.end(logEvent);
       }
     }
-    
+
     private void validateLibraryDirectives() {
       LibraryUnit appLibUnit = context.getAppLibraryUnit();
       for (LibraryUnit lib : libraries.values()) {
@@ -576,7 +620,7 @@ public class DartCompiler {
     private void setEntryPoint() {
       LibraryUnit lib = context.getAppLibraryUnit();
       lib.setEntryNode(new LibraryNode(MAIN_ENTRY_POINT_NAME));
-      // this ensures that if we find it, it's a top-level static element 
+      // this ensures that if we find it, it's a top-level static element
       Element element = lib.getElement().lookupLocalElement(MAIN_ENTRY_POINT_NAME);
       switch (ElementKind.of(element)) {
         case NONE:
@@ -1052,6 +1096,16 @@ public class DartCompiler {
                                   DartCompilerListener listener) throws IOException {
     DartCompilerMainContext context = new DartCompilerMainContext(lib, provider, listener,
                                                                   config);
+    if (config.getCompilerOptions().shouldExposeCoreImpl()) {
+      if (embeddedLibraries == null) {
+        embeddedLibraries = Lists.newArrayList();
+      }
+      // use a place-holder LibrarySource instance, to be replaced when embedded
+      // in the compiler, where the dart uri can be resolved.
+      embeddedLibraries.add(new NamedPlaceHolderLibrarySource("dart:coreimpl"));
+    }
+
+
     new Compiler(lib, embeddedLibraries, config, context).compile();
     int errorCount = context.getErrorCount();
     if (config.typeErrorsAreFatal()) {
@@ -1172,7 +1226,7 @@ public class DartCompiler {
     }
     return null;
   }
-  
+
   public static LibraryUnit getCoreLib(LibraryUnit libraryUnit) {
     return findLibrary(libraryUnit, "corelib.dart", new HashSet<LibraryElement>());
   }