Revert "Revert "First step towards having patch files for generic libraries.""

lib/compiler/implementation/apiimpl.dart

 // Copyright (c) 2012, 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.
 
 #library('leg_apiimpl');
 
 #import('dart:uri');
 
 #import('../compiler.dart', prefix: 'api');
 #import('leg.dart', prefix: 'leg');
@@ skipping 15 matching lines @@
            List<String> options)
     : this.options = options,
       super(
           tracer: new ssa.HTracer(),
           enableTypeAssertions: options.indexOf('--enable-checked-mode') != -1,
           enableUserAssertions: options.indexOf('--enable-checked-mode') != -1,
           emitJavascript: options.indexOf('--output-type=dart') == -1,
           validateUnparse: options.indexOf('--unparse-validation') !== -1);
 
   elements.LibraryElement scanBuiltinLibrary(String path) {
-    Uri uri = libraryRoot.resolve(DART2JS_LIBRARY_MAP[path]);
+    Uri uri = libraryRoot.resolve(DART2JS_LIBRARY_MAP[path].libraryPath);
     elements.LibraryElement library = scanner.loadLibrary(uri, null);
     return library;
   }
 
   void log(message) {
     handler(null, null, null, message, api.Diagnostic.VERBOSE_INFO);
   }
 
   leg.Script readScript(Uri uri, [tree.Node node]) {
     if (uri.scheme == 'dart') uri = translateDartUri(uri, node);
@@ skipping 16 matching lines @@
   }
 
   Uri translateUri(Uri uri, tree.Node node) {
     switch (uri.scheme) {
       case 'package': return translatePackageUri(uri, node);
       default: return uri;
     }
   }
 
   Uri translateDartUri(Uri uri, tree.Node node) {
-    String path = DART2JS_LIBRARY_MAP[uri.path];
+    String path = DART2JS_LIBRARY_MAP[uri.path].libraryPath;
     if (path === null || uri.path.startsWith('_')) {
       reportError(node, 'library not found ${uri}');
       return null;
     }
     if (uri.path == 'dom_deprecated'
         || uri.path == 'html' || uri.path == 'io') {
       // TODO(ahe): Get rid of mockableLibraryUsed when test.dart
       // supports this use case better.
       mockableLibraryUsed = true;
     }
     return libraryRoot.resolve(path);
   }
 
+  Uri resolvePatchUri(String dartLibraryPath) {
+    String patchPath = DART2JS_LIBRARY_MAP[dartLibraryPath].patchPath;
+    if (patchPath === null) return null;
+    return libraryRoot.resolve(patchPath);
+  }
+
   translatePackageUri(Uri uri, tree.Node node) => packageRoot.resolve(uri.path);
 
   bool run(Uri uri) {
     bool success = super.run(uri);
     for (final task in tasks) {
       log('${task.name} took ${task.timing}msec');
     }
     return success;
   }
 
   void reportDiagnostic(leg.SourceSpan span, String message,
                         api.Diagnostic kind) {
     if (kind === api.Diagnostic.ERROR || kind === api.Diagnostic.CRASH) {
       compilationFailed = true;
     }
     if (span === null) {
       handler(null, null, null, message, kind);
     } else {
       handler(translateUri(span.uri, null), span.begin, span.end,
               message, kind);
     }
   }
 
   bool get isMockCompilation() {
     return mockableLibraryUsed
       && (options.indexOf('--allow-mock-compilation') !== -1);
   }
 }