Update homebrew to drop the @2 tab and fix for 2.0

Change-Id: I1ece391c9c7cdcec9fd0662841bdbdaee7a7a373
diff --git a/tools/apps/update_homebrew/lib/update_homebrew.dart b/tools/apps/update_homebrew/lib/update_homebrew.dart
index 521e35d..890a127 100644
--- a/tools/apps/update_homebrew/lib/update_homebrew.dart
+++ b/tools/apps/update_homebrew/lib/update_homebrew.dart
@@ -13,17 +13,14 @@
 
 const FILES = const {
   'dev': const [x64File, ia32File],
-  'stable': const [x64File, ia32File, dartiumFile, contentShellFile]
+  'stable': const [x64File, ia32File]
 };
 
 const urlBase = 'https://storage.googleapis.com/dart-archive/channels';
 const x64File = 'sdk/dartsdk-macos-x64-release.zip';
 const ia32File = 'sdk/dartsdk-macos-ia32-release.zip';
-const dartiumFile = 'dartium/dartium-macos-x64-release.zip';
-const contentShellFile = 'dartium/content_shell-macos-x64-release.zip';
 
 const dartRbFileName = 'dart.rb';
-const dart2RbFileName = 'dart@2.rb';
 
 Future<String> getHash256(
     String channel, String revision, String download) async {
@@ -109,9 +106,6 @@
   await new File(p.join(repository, dartRbFileName)).writeAsString(
       createDartFormula(revisions, hashes, devVersion, stableVersion),
       flush: true);
-  await new File(p.join(repository, dart2RbFileName)).writeAsString(
-      createDart2Formula(revisions, hashes, devVersion, stableVersion),
-      flush: true);
 }
 
 String createDartFormula(
@@ -141,43 +135,10 @@
     end
   end
 
-  option "with-content-shell", "Download and install content_shell -- headless Dartium for testing"
-  option "with-dartium", "Download and install Dartium -- Chromium with Dart"
-
-  resource "content_shell" do
-    version "$stableVersion"
-    url "$urlBase/stable/release/${revisions['stable']}/$contentShellFile"
-    sha256 "${hashes['stable'][contentShellFile]}"
-  end
-
-  resource "dartium" do
-    version "$stableVersion"
-    url "$urlBase/stable/release/${revisions['stable']}/$dartiumFile"
-    sha256 "${hashes['stable'][dartiumFile]}"
-  end
-
   def install
     libexec.install Dir["*"]
     bin.install_symlink "#{libexec}/bin/dart"
     bin.write_exec_script Dir["#{libexec}/bin/{pub,dart?*}"]
-
-    if build.with? "dartium"
-      if build.devel?
-        odie "dartium is no longer supported with --devel builds. Remove --with-dartium and try again."
-      end
-      dartium_binary = "Chromium.app/Contents/MacOS/Chromium"
-      prefix.install resource("dartium")
-      (bin+"dartium").write shim_script dartium_binary
-    end
-
-    if build.with? "content-shell"
-      if build.devel?
-        odie "content-shell is no longer supported with --devel builds. Remove --with-content-shell and try again."
-      end
-      content_shell_binary = "Content Shell.app/Contents/MacOS/Content Shell"
-      prefix.install resource("content_shell")
-      (bin+"content_shell").write shim_script content_shell_binary
-    end
   end
 
   def shim_script(target)
@@ -205,60 +166,6 @@
 end
 ''';
 
-/// TODO: Remove this formula after Dart 2 is released as stable.
-/// This is a transitional mechanism to support developers migrating
-/// from Dart 1 to Dart 2 while it's in pre-release.
-String createDart2Formula(
-        Map revisions, Map hashes, String devVersion, String stableVersion) =>
-    '''
-class DartAT2 < Formula
-  desc "The Dart 2 SDK"
-  homepage "https://www.dartlang.org/"
-  version "$devVersion"
-
-  keg_only :versioned_formula
-
-  if MacOS.prefer_64_bit?
-    url "$urlBase/dev/release/${revisions['dev']}/$x64File"
-    sha256 "${hashes['dev'][x64File]}"
-  else
-    url "$urlBase/dev/release/${revisions['dev']}/$ia32File"
-    sha256 "${hashes['dev'][ia32File]}"
-  end
-
-  def install
-    libexec.install Dir["*"]
-    bin.install_symlink "#{libexec}/bin/dart"
-    bin.write_exec_script Dir["#{libexec}/bin/{pub,dart?*}"]
-  end
-
-  def shim_script(target)
-    <<~EOS
-      #!/usr/bin/env bash
-      exec "#{prefix}/#{target}" "\$@"
-    EOS
-  end
-
-  def caveats; <<~EOS
-    Note that this is a prerelease version of Dart.
-
-    Please note the path to the Dart SDK:
-      #{opt_libexec}
-    EOS
-  end
-
-  test do
-    (testpath/"sample.dart").write <<~EOS
-      void main() {
-        print(r"test message");
-      }
-    EOS
-
-    assert_equal "test message\n", shell_output("#{bin}/dart sample.dart")
-  end
-end
-''';
-
 Future runGit(List<String> args, String repository,
     Map<String, String> gitEnvironment) async {
   print("git ${args.join(' ')}");
diff --git a/tools/apps/update_homebrew/pubspec.yaml b/tools/apps/update_homebrew/pubspec.yaml
index 0645811..7e342b6 100644
--- a/tools/apps/update_homebrew/pubspec.yaml
+++ b/tools/apps/update_homebrew/pubspec.yaml
@@ -2,7 +2,7 @@
 version: 0.1.0
 dependencies:
   _discoveryapis_commons: ^0.1.3+1
-  args: ^0.13.0
+  args: ^1.5.0
   googleapis: ^0.51.0
   http: ^0.11.1+1
   path: ^1.4.1