patch_sdk.dart: Fix Windows build.

tools/patch_sdk.dart

 #!/usr/bin/env dart
 // Copyright (c) 2015, 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.
 
 /// Command line tool to merge the SDK libraries and our patch files.
 /// This is currently designed as an offline tool, but we could automate it.
 
 import 'dart:io';
 import 'dart:async';
@@ skipping 223 matching lines @@
       //   (2) Dart SDK and patch sources.
       // We already collected all inputs from the second category in the deps
       // set. To collect inputs from the first category we actually use Fasta:
       // we ask Fasta to outline patch_sdk.dart and generate a depfile which
       // would list all the sources.
       final depfile = "${outDir}.d";
       await CompilerCommandLine.withGlobalOptions("outline", [
         '--packages',
         new Uri.file(packagesFile).toString(),
         '--platform',
-        platform, // platform.dill that was just generated
+        new Uri.file(platform).toString(), // platform.dill
         Platform.script.toString() // patch_sdk.dart
       ], (CompilerContext c) async {
         CompileTask task =
             new CompileTask(c, new Ticker(isVerbose: c.options.verbose));
         final kernelTarget = await task.buildOutline(null);
         await kernelTarget.writeDepsFile(
             new Uri.file(platform), new Uri.file(depfile));
       });
 
       // Read depfile generated by Fasta and append deps that we have collected
       // during generation of patched_sdk to it.
-      final list = new File(depfile).readAsStringSync().split(':');
+      // Note: we are splitting by ': ' because Windows paths can start with
+      // drive letter followed by a colon.
+      final list = new File(depfile).readAsStringSync().split(': ');
       assert(list.length == 2);
       deps.addAll(list[1].split(' ').where((str) => str.isNotEmpty));
-      assert(list[0] == 'patched_sdk/platform.dill');
+      assert(list[0] == path.join('patched_sdk', 'platform.dill'));
       new File(depfile).writeAsStringSync("${list[0]}: ${deps.join(' ')}\n");
     }, zoneSpecification: new ZoneSpecification(print: (_, _2, _3, line) {
       capturedLines.add(line);
     }));
   } catch (_) {
     for (final line in capturedLines) {
       print(line);
     }
     rethrow;
   }
@@ skipping 337 matching lines @@
     if (diff != 0) return diff;
     return end - other.end;
   }
 }
 
 List<SdkLibrary> _getSdkLibraries(String contents) {
   var libraryBuilder = new SdkLibrariesReader_LibraryBuilder(true);
   parseCompilationUnit(contents).accept(libraryBuilder);
   return libraryBuilder.librariesMap.sdkLibraries;
 }