Don't compile code for desktop zoom or GuestViews on mobile platforms.

chrome/browser/ui/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/chromecast_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 424 matching lines @@
     "webui/user_actions/user_actions_ui.h",
     "webui/user_actions/user_actions_ui_handler.cc",
     "webui/user_actions/user_actions_ui_handler.h",
     "webui/version_handler.cc",
     "webui/version_handler.h",
     "webui/version_handler_chromeos.cc",
     "webui/version_handler_chromeos.h",
     "webui/version_ui.cc",
     "webui/version_ui.h",
     "window_sizer/window_sizer_mac.mm",
-    "zoom/chrome_zoom_level_otr_delegate.cc",
-    "zoom/chrome_zoom_level_otr_delegate.h",
-    "zoom/chrome_zoom_level_prefs.cc",
-    "zoom/chrome_zoom_level_prefs.h",
   ]
 
   defines = []
   libs = []
 
   configs += [
     ":ui_warnings",
     "//build/config:precompiled_headers",
     "//build/config/compiler:wexit_time_destructors",
   ]
@@ skipping 50 matching lines @@
     "//components/device_event_log",
     "//components/dom_distiller/content/browser",
     "//components/dom_distiller/webui",
     "//components/domain_reliability",
     "//components/favicon/content",
     "//components/favicon/core",
     "//components/feedback",
     "//components/flags_ui",
     "//components/gcm_driver",
     "//components/google/core/browser",
-    "//components/guest_view/browser",
     "//components/history/content/browser",
     "//components/image_fetcher/core",
     "//components/infobars/core",
     "//components/invalidation/impl",
     "//components/keyed_service/content",
     "//components/keyed_service/core",
     "//components/metrics:profiler",
     "//components/mime_util",
     "//components/net_log",
     "//components/ntp_snippets",
@@ skipping 44 matching lines @@
     "//components/update_client",
     "//components/upload_list",
     "//components/url_formatter",
     "//components/user_manager",
     "//components/user_prefs",
     "//components/variations",
     "//components/variations/service",
     "//components/version_ui",
     "//components/web_cache/browser",
     "//components/web_resource",
-    "//components/zoom",
     "//content/app/resources",
     "//content/public/common",
     "//crypto",
     "//device/base",
     "//device/bluetooth/public/interfaces:experimental_interfaces",
     "//device/usb",
     "//extensions/features",
     "//media",
     "//net:net",
     "//ppapi/features",
@@ skipping 34 matching lines @@
     "//ui/strings",
     "//ui/surface",
     "//ui/web_dialogs",
     "//v8:v8_version",
   ]
   allow_circular_includes_from = []
 
   if (enable_extensions) {
     deps += [
       "//components/drive",
+      "//components/guest_view/browser",

[msw, 2017/05/12 18:06:32]

Does this belong here? I have no idea what a "guest view" is, or if its related
to extensions, and the class comments in that directory aren't terribly
enlightening. I see that you answered Avi's similar question, but please ask one
of their owners for review of this change, and maybe they'll be inclined to
improve their component name/docs.

[Kevin McNee, 2017/05/15 18:22:18]

I've talked with wjmaclean and lfg offline about this and I've created a bug to
add an explicit build flag for GuestViews instead of relying on extensions (
crbug.com/722453 ). Other GuestView callers are #ifdef'd behind
ENABLE_EXTENSIONS and sometimes !OS_ANDROID, and nothing outside of extensions
currently uses GuestViews, so for now, using enable_extensions here is
reasonable.

       "//extensions/browser",
       "//extensions/strings",
     ]
   }
 
   if (is_chromeos && use_cras) {
     defines += [ "USE_CRAS" ]
   }
 
   if (is_android || is_linux) {
@@ skipping 533 matching lines @@
       "webui/sync_file_system_internals/sync_file_system_internals_ui.cc",
       "webui/sync_file_system_internals/sync_file_system_internals_ui.h",
       "webui/system_info_ui.cc",
       "webui/system_info_ui.h",
       "webui/theme_handler.cc",
       "webui/theme_handler.h",
       "webui/uber/uber_ui.cc",
       "webui/uber/uber_ui.h",
       "window_sizer/window_sizer.cc",
       "window_sizer/window_sizer.h",
+      "zoom/chrome_zoom_level_otr_delegate.cc",
+      "zoom/chrome_zoom_level_otr_delegate.h",
+      "zoom/chrome_zoom_level_prefs.cc",
+      "zoom/chrome_zoom_level_prefs.h",
     ]
     deps += [
       "//apps",
       "//apps/ui/views",
       "//chrome/app/vector_icons",
       "//chrome/browser/profile_resetter:profile_reset_report_proto",
       "//chrome/common:features",
       "//components/feedback/proto",
       "//components/proximity_auth/webui",
       "//components/web_modal",
+      "//components/zoom",
       "//device/bluetooth",
       "//extensions/common:mojo",
       "//mash/public/interfaces",
       "//services/device/public/interfaces",
       "//ui/vector_icons",
     ]
   }
 
   if (enable_basic_printing || enable_print_preview) {
     deps += [ "//printing" ]
@@ skipping 2323 matching lines @@
     ":ui",
   ]
   deps = [
     "//chrome/app/theme:theme_resources",
     "//chrome/browser",
     "//chrome/browser/devtools",
     "//components/password_manager/core/browser",
     "//components/sessions",
     "//components/toolbar",
     "//components/translate/content/browser",
-    "//components/zoom",
     "//content/public/browser",
     "//content/public/common",
     "//content/test:test_support",
     "//net:test_support",
     "//skia",
     "//testing/gtest",
     "//ui/base",
     "//ui/gfx:test_support",
     "//ui/shell_dialogs",
   ]
@@ skipping 28 matching lines @@
       "exclusive_access/fullscreen_controller_test.h",
       "passwords/manage_passwords_ui_controller_mock.cc",
       "passwords/manage_passwords_ui_controller_mock.h",
       "passwords/password_dialog_controller_mock.cc",
       "passwords/password_dialog_controller_mock.h",
       "passwords/passwords_model_delegate_mock.cc",
       "passwords/passwords_model_delegate_mock.h",
       "test/test_confirm_bubble_model.cc",
       "test/test_confirm_bubble_model.h",
     ]
-    deps += [ "//chrome/test:test_support_ui" ]
+    deps += [
+      "//chrome/test:test_support_ui",
+      "//components/zoom",
+    ]
   }
 
   if (enable_extensions) {
     deps += [ "//extensions/browser" ]
   }
 }