Teach sky_tools mojo_run to run on Android (using mojo devtools)

This teaches sky_tools mojo_run --android to invoke mojo's devtool's mojo_run
script with the right flags for invoking sky_viewer on android. This tells the
devtools script to load sky_viewer.mojo from https://storage.googleapis.com/...
and to load app.flx (or whatever the developer specifies as --app) from the
filesystem using the devtools http server.

packages/flutter_tools/lib/src/artifacts.dart

@@ -17,8 +17,8 @@ class _ArtifactStore {
   _ArtifactStore._();
 
   // Keep in sync with https://github.com/flutter/engine/blob/master/sky/tools/big_red_button.py#L50
-  String _googleStorageUrl(String category, String name, String engineRevision) {
-    return 'https://storage.googleapis.com/mojo/sky/${category}/linux-x64/${engineRevision}/${name}';
+  String googleStorageUrl(String category, String platform, String engineRevision) {
+    return 'https://storage.googleapis.com/mojo/sky/${category}/${platform}/${engineRevision}/';
   }
 
   Future _downloadFile(String url, File file) async {
@@ -34,10 +34,6 @@ class _ArtifactStore {
     _logging.fine('Wrote file');
   }
 
-  Future<String> _getEngineRevision(String packageRoot) {
-    return new File(packageRoot + '/sky_engine/REVISION').readAsString();
-  }
-
   Future<Directory> _cacheDir(String engineRevision, String packageRoot) async {
     String cacheDirPath = '${packageRoot}/sky_tools/cache/sky_engine/${engineRevision}/';
     Directory cacheDir = new Directory(cacheDirPath);
@@ -52,8 +48,13 @@ class _ArtifactStore {
     return artifact == Artifact.FlutterCompiler;
   }
 
+
+  Future<String> getEngineRevision(String packageRoot) {
+    return new File(packageRoot + '/sky_engine/REVISION').readAsString();
+  }
+
   Future<String> getPath(Artifact artifact, String packageRoot) async {
-    String engineRevision = await _getEngineRevision(packageRoot);
+    String engineRevision = await getEngineRevision(packageRoot);
     Directory cacheDir = await _cacheDir(engineRevision, packageRoot);
 
     String category, name;
@@ -72,8 +73,8 @@ class _ArtifactStore {
     File cachedFile = new File(cacheDir.path + name);
     if (!await cachedFile.exists()) {
       _logging.info('Downloading ${name} from the cloud, one moment please...');
-      String googleStorageUrl = _googleStorageUrl(category, name, engineRevision);
-      await _downloadFile(googleStorageUrl, cachedFile);
+      String url = googleStorageUrl(category, 'linux-x64', engineRevision) + name;
+      await _downloadFile(url, cachedFile);
       if (_needsToBeExecutable(artifact)) {
         ProcessResult result = await Process.run('chmod', ['u+x', cachedFile.path]);
         if (result.exitCode != 0) throw new Exception(result.stderr);

packages/flutter_tools/lib/src/process.dart

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+library sky_tools.process;
+
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:logging/logging.dart';
+
+final Logger _logging = new Logger('sky_tools.process');
+
+// This runs the command and streams stdout/stderr from the child process to this process' stdout/stderr.
+Future<int> runCommandAndStreamOutput(String command, List<String> args) async {
+  _logging.fine("Starting ${command} with args: ${args}");
+  Process proc = await Process.start(command, args);
+  proc.stdout.transform(UTF8.decoder).listen((data) {
+    stdout.write(data);
+  });
+  proc.stderr.transform(UTF8.decoder).listen((data) {
+    stderr.write(data);
+  });
+  return proc.exitCode;
+}

packages/flutter_tools/lib/src/run_mojo.dart

@@ -5,7 +5,6 @@
 library sky_tools.run_mojo;
 
 import 'dart:async';
-import 'dart:convert';
 import 'dart:io';
 
 import 'package:args/args.dart';
@@ -14,6 +13,7 @@ import 'package:path/path.dart' as path;
 
 import 'artifacts.dart';
 import 'common.dart';
+import 'process.dart';
 
 final Logger _logging = new Logger('sky_tools.run_mojo');
 
@@ -22,10 +22,11 @@ class RunMojoCommandHandler extends CommandHandler {
 
   ArgParser get parser {
     ArgParser parser = new ArgParser();
+    parser.addFlag('android', negatable: false, help: 'Run on an Android device');
     parser.addFlag('help', abbr: 'h', negatable: false);
-    parser.addOption('package-root', defaultsTo: 'packages');
-    parser.addOption('mojo-path', help: 'Path to directory containing mojo_shell and services');
     parser.addOption('app', defaultsTo: 'app.flx');
+    parser.addOption('mojo-path', help: 'Path to directory containing mojo_shell and services');
+    parser.addOption('package-root', defaultsTo: 'packages');
     return parser;
   }
 
@@ -37,6 +38,36 @@ class RunMojoCommandHandler extends CommandHandler {
     return file.absolute.path;
   }
 
+  Future<int> _runAndroid(ArgResults results, String appPath, String engineRevision) async {
+    String skyViewerUrl = artifactStore.googleStorageUrl('viewer', 'android-arm', engineRevision);
+    String command = await _makePathAbsolute(path.join(results['mojo-path'], 'mojo', 'devtools', 'common', 'mojo_run'));
+    String appName = path.basename(appPath);
+    String appDir = path.dirname(appPath);
+    List<String> args = [
+      '--android', '--release', '--embed', 'http://app/$appName',
+      '--map-origin=http://app/=$appDir',
+      '--map-origin=http://sky_viewer/=$skyViewerUrl',
+      '--url-mappings=mojo:sky_viewer=http://sky_viewer/sky_viewer.mojo',
+    ];
+    if (_logging.level <= Level.INFO) {
+      args.add('--verbose');
+      if (_logging.level <= Level.FINE) {
+        args.add('--verbose');
+      }
+    }
+    return runCommandAndStreamOutput(command, args);
+  }
+
+  Future<int> _runLinux(ArgResults results, String appPath, String packageRoot, String engineRevision) async {
+    String viewerPath = await _makePathAbsolute(await artifactStore.getPath(Artifact.SkyViewerMojo, packageRoot));
+    String mojoShellPath = await _makePathAbsolute(path.join(results['mojo-path'], 'out', 'Release', 'mojo_shell'));
+    List<String> mojoRunArgs = [
+      'mojo:window_manager file://${appPath}',
+      '--url-mappings=mojo:window_manager=mojo:kiosk_wm,mojo:sky_viewer=file://${viewerPath}'
+    ];
+    return runCommandAndStreamOutput(mojoShellPath, mojoRunArgs);
+  }
+
   @override
   Future<int> processArgResults(ArgResults results) async {
     if (results['help']) {
@@ -48,23 +79,12 @@ class RunMojoCommandHandler extends CommandHandler {
       return 1;
     }
     String packageRoot = results['package-root'];
+    String engineRevision = await artifactStore.getEngineRevision(packageRoot);
     String appPath = await _makePathAbsolute(results['app']);
-    String viewerPath = await _makePathAbsolute(await artifactStore.getPath(Artifact.SkyViewerMojo, packageRoot));
-    String mojoShellPath = await _makePathAbsolute(path.join(results['mojo-path'], 'mojo_shell'));
-    List<String> mojoRunArgs = [
-      'mojo:window_manager file://${appPath}',
-      '--url-mappings=mojo:window_manager=mojo:kiosk_wm,mojo:sky_viewer=file://${viewerPath}'
-    ];
-    _logging.fine("Starting ${mojoShellPath} with args: ${mojoRunArgs}");
-    Process proc = await Process.start(mojoShellPath, mojoRunArgs);
-    proc.stdout.transform(UTF8.decoder).listen((data) {
-      stdout.write(data);
-    });
-    proc.stderr.transform(UTF8.decoder).listen((data) {
-      stderr.write(data);
-    });
-    int exitCode = await proc.exitCode;
-    if (exitCode != 0) throw new Exception(exitCode);
-    return 0;
+    if (results['android']) {
+      return _runAndroid(results, appPath, engineRevision);
+    } else {
+      return _runLinux(results, appPath, packageRoot, engineRevision);
+    }
   }
 }