Option to disable syntax highlighter and use mostly semantic highlighter. Tests.

compiler/java/com/google/dart/compiler/ast/DartPartOfDirective.java

Index: compiler/java/com/google/dart/compiler/ast/DartPartOfDirective.java
diff --git a/compiler/java/com/google/dart/compiler/ast/DartPartOfDirective.java b/compiler/java/com/google/dart/compiler/ast/DartPartOfDirective.java
index d9bdbe0022a66c4b0f4b440f32db5f90397bbdfa..9d55581301a7b4edfc6d6e990563d2089df03ed2 100644
--- a/compiler/java/com/google/dart/compiler/ast/DartPartOfDirective.java
+++ b/compiler/java/com/google/dart/compiler/ast/DartPartOfDirective.java
@@ -8,12 +8,18 @@ package com.google.dart.compiler.ast;
  * Implements the "part of" directive.
  */
 public class DartPartOfDirective extends DartDirective {
-  private DartExpression name;
+  private final int ofOffset;
+  private final DartExpression name;
 
-  public DartPartOfDirective(DartExpression name) {
+  public DartPartOfDirective(int ofOffset, DartExpression name) {
+    this.ofOffset = ofOffset;
     this.name = becomeParentOf(name);
   }
 
+  public int getOfOffset() {
+    return ofOffset;
+  }
+
   public DartExpression getName() {
     return name;
   }