[CFE] Update flutter_gallery_leak_tester to use flutter/dev/integration_tests/new_gallery

For a few months the "original" flutter gallery has had compile errors
and the weekly bot has been a lot slower (and doesn't really test the
default "advanced invalidation").

This updates the compile target to the one in
flutter/dev/integration_tests/new_gallery which doesn't have compile
time errors.

Change-Id: I59aa701700bc6b3530d73d9c0474dbff525288c5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/430700
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>

pkg/front_end/test/flutter_gallery_leak_tester.dart

diff --git a/pkg/front_end/test/flutter_gallery_leak_tester.dart b/pkg/front_end/test/flutter_gallery_leak_tester.dart
index 731e7f9..95095e2 100644
--- a/pkg/front_end/test/flutter_gallery_leak_tester.dart
+++ b/pkg/front_end/test/flutter_gallery_leak_tester.dart
@@ -61,27 +61,16 @@
 
   Directory gallery = new Directory("$rootPath/gallery");
   if (!gallery.existsSync()) {
-    print("Gallery not found... Attempting to clone via git.");
-    // git clone https://github.com/flutter/gallery.git
-    Process process = await Process.start("git", [
-      "clone",
-      "https://github.com/flutter/gallery.git",
-      "$rootPath/gallery"
-    ]);
-    process.stdout
-        .transform(utf8.decoder)
-        .transform(new LineSplitter())
-        .listen((line) {
-      print("git stdout> $line");
-    });
-    process.stderr
-        .transform(utf8.decoder)
-        .transform(new LineSplitter())
-        .listen((line) {
-      print("git stderr> $line");
-    });
+    print("Gallery not found... Copying from flutter dir.");
+
+    Directory galleryFlutterDev =
+        new Directory("$rootPath/flutter/dev/integration_tests/new_gallery");
+
+    // Copy it.
+    Process process = await Process.start(
+        "cp", ["-r", galleryFlutterDev.path, "$rootPath/gallery"]);
     int processExitCode = await process.exitCode;
-    print("Exit code from git: $processExitCode");
+    print("Exit code from cp: $processExitCode");
 
     process = await Process.start("../flutter/bin/flutter", ["pub", "get"],
         workingDirectory: "$rootPath/gallery/");