Pass uri instead of filepaths when hot-reloading. (#21201)

* Pass uri instead of filepaths when hot-reloading.

Bug: https://github.com/flutter/flutter/issues/21168

* Remove imports. Enable another test

* Restore skipping of test on mac

packages/flutter_tools/lib/src/vmservice.dart

@@ -1149,13 +1149,11 @@ class Isolate extends ServiceObjectOwner {
       final Map<String, dynamic> arguments = <String, dynamic>{
         'pause': pause
       };
-      // TODO(goderbauer): Transfer Uri (instead of file path) when remote end supports it.
-      //     Note: Despite the name, `rootLibUri` and `packagesUri` expect file paths.
       if (rootLibUri != null) {
-        arguments['rootLibUri'] = rootLibUri.toFilePath(windows: false);
+        arguments['rootLibUri'] = rootLibUri.toString();
       }
       if (packagesUri != null) {
-        arguments['packagesUri'] = packagesUri.toFilePath(windows: false);
+        arguments['packagesUri'] = packagesUri.toString();
       }
       final Map<String, dynamic> response = await invokeRpcRaw('_reloadSources', params: arguments);
       return response;

packages/flutter_tools/test/integration/flutter_attach_test.dart

@@ -4,7 +4,6 @@
 
 import 'package:file/file.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
-import 'package:flutter_tools/src/base/platform.dart';
 
 import '../src/common.dart';
 import '../src/context.dart';
@@ -38,7 +37,5 @@ void main() {
       await _flutterAttach.attach(_flutterRun.vmServicePort);
       await _flutterAttach.hotReload();
     });
-    // TODO(dantup): Unskip after flutter-tester is fixed on Windows:
-    // https://github.com/flutter/flutter/issues/17833.
-  }, timeout: const Timeout.factor(6), skip: platform.isWindows);
+  }, timeout: const Timeout.factor(6));
 }

packages/flutter_tools/test/integration/hot_reload_test.dart

@@ -32,9 +32,7 @@ void main() {
     test('works without error', () async {
       await _flutter.run();
       await _flutter.hotReload();
-      // TODO(dantup): Unskip after flutter-tester is fixed on Windows:
-      // https://github.com/flutter/flutter/issues/17833.
-    }, skip: platform.isWindows);
+    });
 
     test('hits breakpoints with file:// prefixes after reload', () async {
       await _flutter.run(withDebugger: true);
@@ -44,12 +42,10 @@ void main() {
           new Uri.file(_project.breakpointFile).toString(),
           _project.breakpointLine);
       expect(isolate.pauseEvent, isInstanceOf<VMPauseBreakpointEvent>());
-      // TODO(dantup): Unskip for Mac when [1] is fixed, unskip on Windows when
-      // both [1] and [2] are fixed.
+
+      // TODO(dantup): Unskip for Mac when [1] is fixed.
       // [1] hot reload/breakpoints fail when uris prefixed with file://
       //     https://github.com/flutter/flutter/issues/18441
-      // [2] flutter-tester doesn't work on Windows
-      //     https://github.com/flutter/flutter/issues/17833
-    }, skip: !platform.isLinux);
+    }, skip: !platform.isLinux && !platform.isWindows);
   }, timeout: const Timeout.factor(6));
 }