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

content/public/browser/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/ui.gni")
 
 # See //content/BUILD.gn for how this works.
 group("browser") {
   if (is_component_build) {
     public_deps = [
@@ skipping 110 matching lines @@
     "gpu_feature_checker.cc",
     "gpu_feature_checker.h",
     "gpu_service_registry.cc",
     "gpu_service_registry.h",
     "gpu_utils.cc",
     "gpu_utils.h",
     "guest_host.h",
     "guest_mode.cc",
     "guest_mode.h",
     "histogram_fetcher.h",
-    "host_zoom_map.h",
     "indexed_db_context.h",
     "indexed_db_info.h",
     "interstitial_page.h",
     "interstitial_page_delegate.cc",
     "interstitial_page_delegate.h",
     "invalidate_type.h",
     "javascript_dialog_manager.cc",
     "javascript_dialog_manager.h",
     "keyboard_event_processing_result.h",
     "load_notification_details.h",
@@ skipping 136 matching lines @@
     "web_drag_dest_delegate.h",
     "web_ui.h",
     "web_ui_controller.cc",
     "web_ui_controller.h",
     "web_ui_controller_factory.h",
     "web_ui_data_source.h",
     "web_ui_message_handler.h",
     "websocket_handshake_request_info.h",
     "worker_service.h",
     "worker_service_observer.h",
-    "zoom_level_delegate.h",
     "zygote_handle_linux.h",
     "zygote_host_linux.h",
   ]
   configs += [
     "//build/config:precompiled_headers",
     "//build/config/compiler:wexit_time_destructors",
     "//content:content_implementation",
   ]
 
   public_deps = [
@@ skipping 36 matching lines @@
   if (is_android) {
     deps += [ "//ui/android" ]
   }
 
   if (use_aura) {
     sources -= [ "context_factory.h" ]
     deps += [ "//ui/aura" ]
   }
 
   if (!is_android) {
-    sources += [ "devtools_frontend_host.h" ]
+    sources += [
+      "devtools_frontend_host.h",
+      "host_zoom_map.h",
+      "zoom_level_delegate.h",
+    ]
   }
 }