[web] adding windows platform to felt. fixing signal

lib/web_ui/dev/browser_lock.yaml

@@ -1,7 +1,8 @@
-chrome:
-  # It seems Chrome can't always release from the same build for all operating
-  # systems, so we specify per-OS build number.
-  Linux: 695653
-  Mac: 695656
-firefox:
-  version: '71.0'
+chrome:
+  # It seems Chrome can't always release from the same build for all operating
+  # systems, so we specify per-OS build number.
+  Linux: 695653
+  Mac: 695656
+  Win: 695655
+firefox:
+  version: '71.0'

lib/web_ui/dev/common.dart

@@ -33,6 +33,8 @@ abstract class PlatformBinding {
         _instance = _LinuxBinding();
       } else if (io.Platform.isMacOS) {
         _instance = _MacBinding();
+      } else if (io.Platform.isWindows) {
+        _instance = _WindowsBinding();
       } else {
         throw '${io.Platform.operatingSystem} is not supported';
       }
@@ -54,6 +56,38 @@ abstract class PlatformBinding {
 const String _kBaseDownloadUrl =
     'https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o';
 
+class _WindowsBinding implements PlatformBinding {
+  @override
+  int getChromeBuild(YamlMap browserLock) {
+    final YamlMap chromeMap = browserLock['chrome'];
+    return chromeMap['Win'];
+  }
+
+  @override
+  String getChromeDownloadUrl(String version) =>
+      'https://www.googleapis.com/download/storage/v1/b/chromium-browser-snapshots/o/Win%2F${version}%2Fchrome-win32.zip?alt=media';
+
+  @override
+  String getChromeExecutablePath(io.Directory versionDir) =>
+      path.join(versionDir.path, 'chrome-win32', 'chrome');
+
+  @override
+  String getFirefoxDownloadUrl(String version) =>
+      'https://download-installer.cdn.mozilla.net/pub/firefox/releases/${version}/win64/en-US/firefox-${version}.exe';
+
+  @override
+  String getFirefoxExecutablePath(io.Directory versionDir) =>
+      path.join(versionDir.path, 'firefox', 'firefox');
+
+  @override
+  String getFirefoxLatestVersionUrl() =>
+      'https://download.mozilla.org/?product=firefox-latest&os=win&lang=en-US';
+
+  @override
+  String getSafariSystemExecutablePath() =>
+      throw UnsupportedError('Safari is not supported on Windows');
+}
+
 class _LinuxBinding implements PlatformBinding {
   @override
   int getChromeBuild(YamlMap browserLock) {

lib/web_ui/dev/felt.dart

@@ -51,8 +51,12 @@ void _listenToShutdownSignals() {
     print('Received SIGINT. Shutting down.');
     io.exit(1);
   });
-  io.ProcessSignal.sigterm.watch().listen((_) {
-    print('Received SIGTERM. Shutting down.');
-    io.exit(1);
-  });
+  // SIGTERM signals are not generated under Windows.
+  // See https://docs.microsoft.com/en-us/previous-versions/xdkz3x12(v%3Dvs.140)
+  if (!io.Platform.isWindows) {
+    io.ProcessSignal.sigterm.watch().listen((_) {
+      print('Received SIGTERM. Shutting down.');
+      io.exit(1);
+    });
+  }
 }