Small changes to get the compilation size of code importing dart:html shorter.

lib/compiler/implementation/compiler.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.
 
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
 final bool REPORT_EXCESS_RESOLUTION = false;
@@ skipping 282 matching lines @@
     enqueuer.resolution.addToWorkList(
         element.find(const SourceString('_currentIsolate')));
     enqueuer.resolution.addToWorkList(
         element.find(const SourceString('_callInIsolate')));
     enqueuer.codegen.addToWorkList(element.find(START_ROOT_ISOLATE));
   }
 
   bool hasIsolateSupport() => isolateLibrary !== null;
 
   void onLibraryLoaded(LibraryElement library, Uri uri) {
-    if (uri.toString() == 'dart:isolate') {
-      enableIsolateSupport(library);
-    }
     if (dynamicClass !== null) {
       // When loading the built-in libraries, dynamicClass is null. We
       // take advantage of this as core and coreimpl import js_helper
       // and see Dynamic this way.
       withCurrentElement(dynamicClass, () {
         library.addToScope(dynamicClass, this);
       });
     }
   }
 
@@ skipping 580 matching lines @@
     final endOffset = end.charOffset + end.slowCharCount;
 
     // [begin] and [end] might be the same for the same empty token. This
     // happens for instance when scanning '$$'.
     assert(endOffset >= beginOffset);
     return f(beginOffset, endOffset);
   }
 
   String toString() => 'SourceSpan($uri, $begin, $end)';
 }