Removes dartc reliance on its own libraries, now can be targeted at any implementation's libraries

compiler/java/com/google/dart/compiler/UrlSource.java

Index: compiler/java/com/google/dart/compiler/UrlSource.java
diff --git a/compiler/java/com/google/dart/compiler/UrlSource.java b/compiler/java/com/google/dart/compiler/UrlSource.java
index b5f805d5720ef26a7063cf272568badd18553e02..b71ed09a908af3ab0cb91ae5d437fcf58a435ff8 100644
--- a/compiler/java/com/google/dart/compiler/UrlSource.java
+++ b/compiler/java/com/google/dart/compiler/UrlSource.java
@@ -31,6 +31,9 @@ public abstract class UrlSource implements Source {
 
   private final URI uri;
   private final URI absoluteUri;
+  /**
+   * original URI translated into a file: URI
+   */
   private final URI translatedUri;
   private final boolean shouldCareAboutLastModified;
   private volatile boolean exists = false;
@@ -68,6 +71,7 @@ public abstract class UrlSource implements Source {
 
   protected UrlSource(File file) {
     URI uri = file.toURI().normalize();
+   
     if (!file.exists()) {
       // TODO(jgw): This is a bit ugly, but some of the test infrastructure depends upon
       // non-existant relative files being looked up as classpath resources. This was
@@ -79,7 +83,10 @@ public abstract class UrlSource implements Source {
     }
 
     this.uri = BASE_URI.relativize(uri);
-    this.translatedUri = this.absoluteUri = BASE_URI.resolve(uri);
+    this.translatedUri = this.absoluteUri = BASE_URI.resolve(uri);	
+
+    	
+    
     this.systemLibraryManager = null;
     this.shouldCareAboutLastModified = true;
   }