Create ExternalAuthGoogleDelegate

* Create ExternalAuthGoogleDelegate, owned by ExternalAuthUtils, which
  will be used to implement isGoogleSigned downstream, rather than doing
  so with an overriding subclass.
* This is patch 1/5 for providing ExternalAuthUtils as a singleton
  instead of from AppHooks.

This is a reland of
https://chromium-review.googlesource.com/c/chromium/src/+/2587429
except ExternalAuthGoogleDelegate is not yet used in ExternalAuthUtils.
That part will be implemented in the following chromium patch after
downstream implements ExternalAuthGoogleDelegateImpl.

Bug: 1154371
Change-Id: I4fd71fb81f6999be7eb26cfcb0cc121ce38f4590
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2593748Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Nick Burris <nburris@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837164}

chrome/android/BUILD.gn

@@ -883,6 +883,7 @@ junit_binary("chrome_junit_tests") {
     "//components/embedder_support/android:context_menu_java",
     "//components/embedder_support/android:junit_test_support",
     "//components/embedder_support/android:util_java",
+    "//components/externalauth/android:google_delegate_public_impl_java",
     "//components/externalauth/android:java",
     "//components/externalauth/android:junit",
     "//components/favicon/android:java",
@@ -1156,6 +1157,7 @@ android_library("chrome_test_java") {
     "//components/embedder_support/android:web_contents_delegate_java",
     "//components/external_intents/android:java",
     "//components/external_intents/android:javatests",
+    "//components/externalauth/android:google_delegate_public_impl_java",
     "//components/externalauth/android:java",
     "//components/favicon/android:java",
     "//components/feature_engagement:feature_engagement_java",
@@ -1941,6 +1943,7 @@ java_group("chrome_public_base_module_java") {
   deps = [
     ":app_hooks_java",
     ":chrome_all_java",
+    "//components/externalauth/android:google_delegate_public_impl_java",
   ]
 }
 
@@ -2352,7 +2355,10 @@ template("monochrome_public_apk_or_module_tmpl") {
     if (_enable_chrome_module) {
       deps += [ "//chrome/android:chrome_base_module_resources" ]
     } else {
-      deps += [ "//chrome/android:app_hooks_java" ]
+      deps += [
+        "//chrome/android:app_hooks_java",
+        "//components/externalauth/android:google_delegate_public_impl_java",
+      ]
     }
     if (!_is_trichrome) {
       deps += [
@@ -3005,7 +3011,10 @@ template("monochrome_or_trichrome_public_bundle_tmpl") {
     module_descs = _module_descs
     version_code = _version_code
     if (enable_chrome_module) {
-      chrome_deps = [ "//chrome/android:app_hooks_java" ]
+      chrome_deps = [
+        "//chrome/android:app_hooks_java",
+        "//components/externalauth/android:google_delegate_public_impl_java",
+      ]
       if (!_is_trichrome) {
         chrome_deps += [ "//chrome/android:monochrome_java" ]
       }

chrome/test/BUILD.gn

@@ -547,6 +547,7 @@ if (is_android) {
       "//chrome/browser/profiling_host:profiling_browsertests",
       "//components/browser_ui/widget/android:java",
       "//components/crash/android:crashpad_main",
+      "//components/externalauth/android:google_delegate_public_impl_java",
       "//components/games/core/test:test_support",
       "//components/metrics/demographics:test_support",
       "//components/page_load_metrics/browser:test_support",
@@ -4386,6 +4387,7 @@ test("unit_tests") {
       "//chrome/browser/updates:unit_tests",
       "//chrome/services/media_gallery_util:unit_tests",
       "//components/download/internal/common:internal_java",
+      "//components/externalauth/android:google_delegate_public_impl_java",
       "//components/favicon/core/test:test_support",
       "//components/gcm_driver/instance_id/android:instance_id_driver_java",
       "//components/gcm_driver/instance_id/android:instance_id_driver_test_support_java",

components/externalauth/android/BUILD.gn

@@ -4,6 +4,26 @@
 
 import("//build/config/android/rules.gni")
 
+# Separate target to allow for a dependency on GmsCore. It compiles the abstract class;
+# implementations are compiled separately.
+android_library("google_delegate_java") {
+  sources = [
+    "java/src/org/chromium/components/externalauth/ExternalAuthGoogleDelegate.java",
+    "java/src/org/chromium/components/externalauth/ExternalAuthGoogleDelegateImpl.java",
+  ]
+
+  # Add the actual implementation where necessary so that downstream targets
+  # can provide their own implementations.
+  jar_excluded_patterns = [ "*/ExternalAuthGoogleDelegateImpl.class" ]
+}
+
+# This target compiles the implementation of ExternalAuthGoogleDelegate for
+# public targets.
+android_library("google_delegate_public_impl_java") {
+  sources = [ "java/src/org/chromium/components/externalauth/ExternalAuthGoogleDelegateImpl.java" ]
+  deps = [ ":google_delegate_java" ]
+}
+
 android_library("java") {
   deps = [
     "$google_play_services_package:google_play_services_base_java",

components/externalauth/android/java/src/org/chromium/components/externalauth/ExternalAuthGoogleDelegate.java

+// Copyright 2020 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.
+
+package org.chromium.components.externalauth;
+
+/**
+ * Base class for defining methods where different behavior is required by downstream targets.
+ * The correct version of {@link ExternalAuthGoogleDelegateImpl} will be determined at compile time
+ * via build rules.
+ */
+public class ExternalAuthGoogleDelegate {
+    /**
+     * Returns whether the call is originating from a Google-signed package.
+     * @param packageName The package name to inquire about.
+     */
+    public boolean isGoogleSigned(String packageName) {
+        return false;
+    }
+}

components/externalauth/android/java/src/org/chromium/components/externalauth/ExternalAuthGoogleDelegateImpl.java

+// Copyright 2020 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.
+
+package org.chromium.components.externalauth;
+
+/**
+ * Instantiable version of {@link ExternalAuthGoogleDelegate}, don't add anything to this class!
+ * Downstream targets may provide a different implementation. In GN, we specify that
+ * {@link ExternalAuthGoogleDelegate} is compiled separately from its implementation; other
+ * projects may specify a different ExternalAuthGoogleDelegateImpl via GN.
+ */
+public class ExternalAuthGoogleDelegateImpl extends ExternalAuthGoogleDelegate {}