Change a few more uses of the old try-catch syntax.

pkg/dartdoc/mirrors/dart2js_mirror.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('mirrors.dart2js');
 
 #import('../../../lib/compiler/compiler.dart', prefix: 'diagnostics');
 #import('../../../lib/compiler/implementation/elements/elements.dart');
 #import('../../../lib/compiler/implementation/apiimpl.dart', prefix: 'api');
 #import('../../../lib/compiler/implementation/scanner/scannerlib.dart');
@@ skipping 194 matching lines @@
     bool success = _runList(uriList);
     for (final task in tasks) {
       log('${task.name} took ${task.timing}msec');
     }
     return success;
   }
 
   bool _runList(List<Uri> uriList) {
     try {
       runCompilerList(uriList);
-    } catch (CompilerCancelledException exception) {
+    } on CompilerCancelledException catch (exception) {
       log(exception.toString());
       log('compilation failed');
       return false;
     }
     tracer.close();
     log('compilation succeeded');
     return true;
   }
 
   void runCompilerList(List<Uri> uriList) {
@@ skipping 61 matching lines @@
   bool isAborting = false;
   Map<String, SourceFile> sourceFiles;
 
   Future<String> provider(Uri uri) {
     if (uri.scheme != 'file') {
       throw new IllegalArgumentException(uri);
     }
     String source;
     try {
       source = readAll(uriPathToNative(uri.path));
-    } catch (FileIOException ex) {
+    } on FileIOException catch (ex) {
       throw 'Error: Cannot read "${relativize(cwd, uri)}" (${ex.osError}).';
     }
     sourceFiles[uri.toString()] =
       new SourceFile(relativize(cwd, uri), source);
     return new Future.immediate(source);
   }
 
   void handler(Uri uri, int begin, int end,
                String message, diagnostics.Diagnostic kind) {
     if (isAborting) return;
@@ skipping 1073 matching lines @@
     if (node !== null) {
       var span = system.compiler.spanFromNode(node, script.uri);
       return new Dart2JsLocation(script, span);
     } else {
       var span = system.compiler.spanFromElement(_variable);
       return new Dart2JsLocation(script, span);
     }
   }
 }