Revert "Add empty ClassRegister.java"

This reverts commit 1cbb34fc.

Reason for revert: Culprit for official build failures, confirmed by a local build.

Original change's description:
> Add empty ClassRegister.java
> 
> Split ClassRegister out from http://crrev/c/923021.
> 
> Introduces ClassRegsiter to upstream, but don't make any use of it
> until the corresponding downstream part is added.
> 
> Bug: 805531
> Change-Id: I42db76afd1a78e70208876f8a8a9120b34cf2d44
> Reviewed-on: https://chromium-review.googlesource.com/949611
> Reviewed-by: David Trainor <dtrainor@chromium.org>
> Commit-Queue: Shimi Zhang <ctzsm@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#540974}

TBR=dtrainor@chromium.org,ctzsm@chromium.org

Change-Id: If1b772d23b0aa26ec9efa39756181b4f4dfdb298
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 805531
Reviewed-on: https://chromium-review.googlesource.com/950802Reviewed-by: Alexandr Ilin <alexilin@chromium.org>
Commit-Queue: Alexandr Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541058}

chrome/android/BUILD.gn

@@ -40,8 +40,6 @@ chrome_sync_shell_jinja_variables =
     [ "manifest_package=org.chromium.chrome.sync_shell" ]
 
 app_hooks_impl = "java/src/org/chromium/chrome/browser/AppHooksImpl.java"
-class_register_impl =
-    "java/src/org/chromium/chrome/browser/ClassRegisterImpl.java"
 
 if (enable_resource_whitelist_generation) {
   monochrome_resource_whitelist =
@@ -172,13 +170,6 @@ android_library("app_hooks_java") {
   ]
 }
 
-android_library("class_register_java") {
-  java_files = [ class_register_impl ]
-  deps = [
-    ":chrome_java",
-  ]
-}
-
 android_aidl("photo_picker_aidl") {
   import_include = [ "java/src/org/chromium/chrome/browser/photo_picker" ]
   sources = [
@@ -331,10 +322,7 @@ android_library("chrome_java") {
   android_manifest_for_lint = chrome_public_android_manifest
 
   # From java_sources.gni.
-  java_files = chrome_java_sources + [
-                 app_hooks_impl,
-                 class_register_impl,
-               ]
+  java_files = chrome_java_sources + [ app_hooks_impl ]
 
   if (enable_vr) {
     java_files += chrome_vr_java_sources
@@ -348,10 +336,7 @@ android_library("chrome_java") {
 
   # Add the actual implementation where necessary so that downstream targets
   # can provide their own implementations.
-  jar_excluded_patterns = [
-    "*/AppHooksImpl.class",
-    "*/ClassRegisterImpl.class",
-  ]
+  jar_excluded_patterns = [ "*/AppHooksImpl.class" ]
 }
 
 action("chrome_android_java_google_api_keys_srcjar") {
@@ -432,7 +417,6 @@ junit_binary("chrome_junit_tests") {
     ":app_hooks_java",
     ":chrome_java",
     ":chrome_java_resources",
-    ":class_register_java",
     ":partner_location_descriptor_proto_java",
     "$google_play_services_package:google_play_services_base_java",
     "$google_play_services_package:google_play_services_basement_java",
@@ -520,7 +504,6 @@ android_library("chrome_test_java") {
     "//base:base_java_test_support",
     "//chrome/android:app_hooks_java",
     "//chrome/android:chrome_java",
-    "//chrome/android:class_register_java",
     "//chrome/android/third_party/compositor_animator:compositor_animator_java",
     "//chrome/android/third_party/widget_bottomsheet_base:widget_bottomsheet_base_java",
     "//chrome/android/webapk/libs/client:client_java",
@@ -672,7 +655,6 @@ if (enable_vr) {
       "//base:base_java_test_support",
       "//chrome/android:app_hooks_java",
       "//chrome/android:chrome_java",
-      "//chrome/android:class_register_java",
       "//chrome/test/android:chrome_java_test_support",
       "//components/policy/android:policy_java",
       "//content/public/android:content_java",
@@ -1076,7 +1058,6 @@ template("chrome_public_apk_tmpl_shared") {
       ":chrome_public_apk_resources",
       ":chrome_public_non_pak_assets",
       ":chrome_public_pak_assets",
-      ":class_register_java",
       "//base:base_java",
     ]
   }
@@ -1143,7 +1124,6 @@ monochrome_public_apk_tmpl("monochrome_public_apk") {
     "//base:base_java",
     "//chrome/android:app_hooks_java",
     "//chrome/android:chrome_java",
-    "//chrome/android:class_register_java",
   ]
 }
 
@@ -1295,7 +1275,6 @@ instrumentation_test_apk("chrome_sync_shell_test_apk") {
     "//base:base_java_test_support",
     "//chrome/android:app_hooks_java",
     "//chrome/android:chrome_java",
-    "//chrome/android:class_register_java",
     "//chrome/test/android:chrome_java_test_support",
     "//components/bookmarks/common/android:bookmarks_java",
     "//components/policy/android:policy_java",

chrome/android/java/src/org/chromium/chrome/browser/ClassRegister.java

-// Copyright 2018 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.chrome.browser;
-
-/**
- * Base class for defining methods where different behavior is required by downstream targets.
- * The difference to AppHooks is we need to upstream changes here later.
- */
-public abstract class ClassRegister {
-    private static ClassRegisterImpl sInstance;
-
-    public static ClassRegister get() {
-        if (sInstance == null) {
-            sInstance = new ClassRegisterImpl();
-        }
-        return sInstance;
-    }
-
-    /**
-     * Register the {@link ContentClassFactory} so {@link SelectionInsertionHandleObserver} can be
-     * set properly.
-     */
-    public void registerContentClassFactory() {
-        /* no-op */
-    }
-}

chrome/android/java/src/org/chromium/chrome/browser/ClassRegisterImpl.java

-// Copyright 2018 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.chrome.browser;
-
-/**
- * Implementation of {@link ClassRegister}, don't add anything to this class.
- * Downstream targets may provide a different implemenation.
- */
-public class ClassRegisterImpl extends ClassRegister {}

chrome/android/java_sources.gni

@@ -34,7 +34,6 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/ChromeTabbedActivity2.java",
   "java/src/org/chromium/chrome/browser/ChromeVersionInfo.java",
   "java/src/org/chromium/chrome/browser/ChromeWindow.java",
-  "java/src/org/chromium/chrome/browser/ClassRegister.java",
   "java/src/org/chromium/chrome/browser/DefaultBrowserInfo.java",
   "java/src/org/chromium/chrome/browser/DeferredStartupHandler.java",
   "java/src/org/chromium/chrome/browser/DevToolsServer.java",

chrome/test/BUILD.gn

@@ -422,7 +422,6 @@ test("browser_tests") {
     deps += [
       "//chrome/android:app_hooks_java",
       "//chrome/android:chrome_java",
-      "//chrome/android:class_register_java",
       "//v8:v8_external_startup_data_assets",
     ]
 
@@ -2807,7 +2806,6 @@ test("unit_tests") {
       "//base:base_java",
       "//chrome/android:app_hooks_java",
       "//chrome/android:chrome_java",
-      "//chrome/android:class_register_java",
       "//components/gcm_driver/instance_id/android:instance_id_driver_java",
       "//components/gcm_driver/instance_id/android:instance_id_driver_test_support_java",
       "//content/public/android:content_java",