let the embedding maven engine dependency reference the storage proxy (#56164)

dev/devicelab/bin/tasks/android_engine_dependency_proxy_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:flutter_devicelab/framework/apk_utils.dart';
+import 'package:flutter_devicelab/framework/framework.dart';
+import 'package:flutter_devicelab/framework/utils.dart';
+import 'package:path/path.dart' as path;
+
+final String gradlew = Platform.isWindows ? 'gradlew.bat' : 'gradlew';
+final String gradlewExecutable = Platform.isWindows ? '.\\$gradlew' : './$gradlew';
+
+/// Tests that we respect storage proxy URLs in gradle dependencies.
+Future<void> main() async {
+  await task(() async {
+    section('Find Java');
+
+    final String javaHome = await findJavaHome();
+    if (javaHome == null)
+      return TaskResult.failure('Could not find Java');
+    print('\nUsing JAVA_HOME=$javaHome');
+
+    section('Create project');
+    await runProjectTest((FlutterProject flutterProject) async {
+      await inDirectory(path.join(flutterProject.rootPath, 'android'), () async {
+        section('Insert gradle testing script');
+        final File build = File(path.join(
+            flutterProject.rootPath, 'android', 'app', 'build.gradle'));
+        build.writeAsStringSync(
+          '''
+task printEngineMavenUrl() {
+    doLast {
+        println project.repositories.find { it.name == 'maven' }.url
+    }
+}
+          ''',
+          mode: FileMode.append,
+          flush: true,
+        );
+
+        section('Checking default maven URL');
+        String mavenUrl = await eval(
+          gradlewExecutable,
+          <String>['printEngineMavenUrl', '-q'],
+        );
+
+        if (mavenUrl != 'https://storage.googleapis.com/download.flutter.io') {
+          throw TaskResult.failure('Expected Android engine maven dependency URL to '
+          'resolve to https://storage.googleapis.com/download.flutter.io. Got '
+          '$mavenUrl instead');
+        }
+
+        section('Checking overriden maven URL');
+        mavenUrl = await eval(
+          gradlewExecutable,
+          <String>['printEngineMavenUrl', '-q'],
+          environment: <String, String>{
+            'FLUTTER_STORAGE_BASE_URL': 'my.special.proxy',
+          }
+        );
+
+        if (mavenUrl != 'https://my.special.proxy/download.flutter.io') {
+          throw TaskResult.failure('Expected overriden Android engine maven '
+          'dependency URL to resolve to proxy location '
+          'https://my.special.proxy/download.flutter.io. Got '
+          '$mavenUrl instead');
+        }
+      });
+    });
+    return TaskResult.success(null);
+  });
+}

packages/flutter_tools/gradle/aar_init_script.gradle

@@ -53,11 +53,12 @@ void configureProject(Project project, String outputDir) {
             "See: https://github.com/flutter/flutter/issues/40866")
     }
 
+    String storageUrl = System.getenv('FLUTTER_STORAGE_BASE_URL') ?: "storage.googleapis.com"
     // This is a Flutter plugin project. Plugin projects don't apply the Flutter Gradle plugin,
     // as a result, add the dependency on the embedding.
     project.repositories {
         maven {
-            url "https://storage.googleapis.com/download.flutter.io"
+            url "https://$storageUrl/download.flutter.io"
         }
     }
     String engineVersion = Paths.get(getFlutterRoot(project), "bin", "internal", "engine.version")

packages/flutter_tools/gradle/flutter.gradle

@@ -41,7 +41,7 @@ android {
 apply plugin: FlutterPlugin
 
 class FlutterPlugin implements Plugin<Project> {
-    private static final String MAVEN_REPO      = "https://storage.googleapis.com/download.flutter.io";
+    private static final String DEFAULT_MAVEN_HOST = "storage.googleapis.com";
 
     // The platforms that can be passed to the `--Ptarget-platform` flag.
     private static final String PLATFORM_ARM32  = "android-arm";
@@ -200,10 +200,10 @@ class FlutterPlugin implements Plugin<Project> {
         if (!supportsBuildMode(flutterBuildMode)) {
             return
         }
+        String hostedRepository = System.env.FLUTTER_STORAGE_BASE_URL ?: DEFAULT_MAVEN_HOST
         String repository = useLocalEngine()
             ? project.property('local-engine-repo')
-            : MAVEN_REPO
-
+            : "https://$hostedRepository/download.flutter.io"
         project.rootProject.allprojects {
             repositories {
                 maven {

packages/flutter_tools/gradle/resolve_dependencies.gradle

@@ -14,11 +14,13 @@
 
 import java.nio.file.Paths
 
+String storageUrl = System.getenv('FLUTTER_STORAGE_BASE_URL') ?: "storage.googleapis.com"
+
 repositories {
     google()
     jcenter()
     maven {
-        url "https://storage.googleapis.com/download.flutter.io"
+        url "https://$storageUrl/download.flutter.io"
     }
 }
 

packages/flutter_tools/lib/src/android/gradle.dart

@@ -648,12 +648,13 @@ void printHowToConsumeAar({
   1. Open ${fileSystem.path.join('<host>', 'app', 'build.gradle')}
   2. Ensure you have the repositories configured, otherwise add them:
 
+      String storageUrl = System.env.FLUTTER_STORAGE_BASE_URL ?: "storage.googleapis.com"
       repositories {
         maven {
             url '${repoDirectory.path}'
         }
         maven {
-            url 'https://storage.googleapis.com/download.flutter.io'
+            url 'https://\$storageUrl/download.flutter.io'
         }
       }
 

packages/flutter_tools/test/general.shard/android/gradle_test.dart

@@ -2343,12 +2343,13 @@ plugin1=${plugin1.path}
           '  1. Open <host>/app/build.gradle\n'
           '  2. Ensure you have the repositories configured, otherwise add them:\n'
           '\n'
+          '      String storageUrl = System.env.FLUTTER_STORAGE_BASE_URL ?: "storage.googleapis.com"\n'
           '      repositories {\n'
           '        maven {\n'
           "            url 'build/'\n"
           '        }\n'
           '        maven {\n'
-          "            url 'https://storage.googleapis.com/download.flutter.io'\n"
+          "            url 'https://\$storageUrl/download.flutter.io'\n"
           '        }\n'
           '      }\n'
           '\n'
@@ -2393,12 +2394,13 @@ plugin1=${plugin1.path}
           '  1. Open <host>/app/build.gradle\n'
           '  2. Ensure you have the repositories configured, otherwise add them:\n'
           '\n'
+          '      String storageUrl = System.env.FLUTTER_STORAGE_BASE_URL ?: "storage.googleapis.com"\n'
           '      repositories {\n'
           '        maven {\n'
           "            url 'build/'\n"
           '        }\n'
           '        maven {\n'
-          "            url 'https://storage.googleapis.com/download.flutter.io'\n"
+          "            url 'https://\$storageUrl/download.flutter.io'\n"
           '        }\n'
           '      }\n'
           '\n'
@@ -2430,12 +2432,13 @@ plugin1=${plugin1.path}
           '  1. Open <host>/app/build.gradle\n'
           '  2. Ensure you have the repositories configured, otherwise add them:\n'
           '\n'
+          '      String storageUrl = System.env.FLUTTER_STORAGE_BASE_URL ?: "storage.googleapis.com"\n'
           '      repositories {\n'
           '        maven {\n'
           "            url 'build/'\n"
           '        }\n'
           '        maven {\n'
-          "            url 'https://storage.googleapis.com/download.flutter.io'\n"
+          "            url 'https://\$storageUrl/download.flutter.io'\n"
           '        }\n'
           '      }\n'
           '\n'
@@ -2468,12 +2471,13 @@ plugin1=${plugin1.path}
           '  1. Open <host>/app/build.gradle\n'
           '  2. Ensure you have the repositories configured, otherwise add them:\n'
           '\n'
+          '      String storageUrl = System.env.FLUTTER_STORAGE_BASE_URL ?: "storage.googleapis.com"\n'
           '      repositories {\n'
           '        maven {\n'
           "            url 'build/'\n"
           '        }\n'
           '        maven {\n'
-          "            url 'https://storage.googleapis.com/download.flutter.io'\n"
+          "            url 'https://\$storageUrl/download.flutter.io'\n"
           '        }\n'
           '      }\n'
           '\n'