Fix for extra memory consumption.

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

 // Copyright (c) 2011, 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.
 
 package com.google.dart.compiler;
 
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.google.common.collect.Sets.SetView;
 import com.google.common.io.CharStreams;
@@ skipping 501 matching lines @@
           LibraryDeps deps = lib.getDeps(context);
 
           // Prepare all top-level symbols.
           Set<String> oldTopLevelSymbols = Sets.newHashSet();
           for (LibraryDeps.Source source : deps.getSources()) {
             oldTopLevelSymbols.addAll(source.getTopSymbols());
           }
 
           // Parse units that are out-of-date with respect to their dependencies.
           for (DartUnit unit : lib.getUnits()) {
-            String relPath = unit.getSource().getRelativePath();
-            LibraryDeps.Source source = deps.getSource(relPath);
-            if (isUnitOutOfDate(lib, source)) {
-              filesHaveChanged = true;
-              DartSource dartSrc = lib.getSource().getSourceFor(relPath);
-              if (dartSrc != null && dartSrc.exists()) {
-                unit = parse(dartSrc, lib.getPrefixes(), false);
-                if (unit != null) {
-                  lib.putUnit(unit);
+            if (unit.isDiet()) {
+              String relPath = unit.getSource().getRelativePath();
+              LibraryDeps.Source source = deps.getSource(relPath);
+              if (isUnitOutOfDate(lib, source)) {
+                filesHaveChanged = true;
+                DartSource dartSrc = lib.getSource().getSourceFor(relPath);
+                if (dartSrc != null && dartSrc.exists()) {
+                  unit = parse(dartSrc, lib.getPrefixes(), false);
+                  if (unit != null) {
+                    lib.putUnit(unit);
+                  }
                 }
               }
             }
           }
         }
 
         if (filesHaveChanged) {
           context.setFilesHaveChanged();
         }
       } finally {
@@ skipping 763 matching lines @@
         return unit;
       }
     }
     return null;
   }
 
   public static LibraryUnit getCoreLib(LibraryUnit libraryUnit) {
     return findLibrary(libraryUnit, "corelib.dart", new HashSet<LibraryElement>());
   }
 }