Add --update-perfetto option to build scripts (flutter#4581)

Author: kenzieschmoll

tool/build_e2e.dart

@@ -5,8 +5,11 @@
 import 'dart:io';
 
 const argDevToolsBuild = 'devtools-build';
+const argUpdatePerfetto = '--update-perfetto';
 
 void main(List<String> args) async {
+  final shouldUpdatePerfetto = args.contains(argUpdatePerfetto);
+
   final mainDevToolsDirectory = Directory.current;
   if (!mainDevToolsDirectory.path.endsWith('/devtools')) {
     throw Exception('Please execute this script from your top level '
@@ -23,7 +26,9 @@ void main(List<String> args) async {
   print('Running the build_release.sh script...');
   final buildProcess = await Process.start(
     './tool/build_release.sh',
-    [],
+    [
+      if (shouldUpdatePerfetto) argUpdatePerfetto,
+    ],
     workingDirectory: mainDevToolsDirectory.path,
   );
   _forwardOutputStreams(buildProcess);

tool/build_release.sh

@@ -4,11 +4,20 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+# Contains a path to this script, relative to the directory it was called from.
+RELATIVE_PATH_TO_SCRIPT="${BASH_SOURCE[0]}"
+
+# The directory that this script is located in.
+TOOL_DIR=`dirname "${RELATIVE_PATH_TO_SCRIPT}"`
+
+# The devtools root directory is assumed to be the parent of this directory.
+DEVTOOLS_DIR="${TOOL_DIR}/.."
+
 # Use the Flutter SDK from flutter-sdk/.
 FLUTTER_DIR="`pwd`/flutter-sdk"
 PATH="$FLUTTER_DIR/bin":$PATH
 
-REQUIRED_FLUTTER_VERSION=$(<"flutter-version.txt")
+REQUIRED_FLUTTER_VERSION=$(<"${DEVTOOLS_DIR}/flutter-version.txt")
 
 flutter --version
 ACTUAL_FLUTTER_VERSION=$(<"$FLUTTER_DIR/version")
@@ -26,7 +35,11 @@ fi
 # echo on
 set -ex
 
-pushd packages/devtools_app
+if [[ $1 = "--update-perfetto" ]]; then
+  $TOOL_DIR/update_perfetto.sh
+fi
+
+pushd $DEVTOOLS_DIR/packages/devtools_app
 
 flutter clean
 rm -rf build/web