Android: Do not build any extensions code except for extensions_constants.

chrome/common/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("//tools/grit/grit_rule.gni")
 
 gypi_values = exec_script(
     "//build/gypi_to_gn.py",
     [ rebase_path("../chrome_common.gypi") ],
     "scope",
     [ "../chrome_common.gypi" ])
 
 # GYP version: chrome/chrome_resources.gyp:chrome_resources
 #              (generate_common_resources action)
 grit("resources") {
   source = "common_resources.grd"
   output_dir = "$root_gen_dir/chrome"
   output_name = "common_resources"
   outputs = [
     "grit/common_resources.h",
     "common_resources.pak",
   ]
 }
 
 # GYP version: chrome/chrome_resources.gyp:chrome_resources
 #              (generate_extensions_api_resources action)
+if (enable_extensions) {
+
 grit("extensions_api_resources") {
   source = "extensions_api_resources.grd"
   output_dir = "$root_gen_dir/chrome"
   outputs = [
     "grit/extensions_api_resources.h",
     "extensions_api_resources.pak",
   ]
 }
 
+}
+
 # GYP version: chrome/chrome_common.gyp:common
 static_library("common") {
   sources = rebase_path(gypi_values.chrome_common_sources, ".", "//chrome")
   defines = []
 
   configs += [ "//build/config/compiler:wexit_time_destructors" ]
 
   deps = [
     ":version",
     "//base:base",
     "//base:i18n",
     "//base:prefs",
     "//base:base_static",
     "//chrome:resources",
     "//chrome:strings",
     "//chrome/app/theme:theme_resources",
     "//chrome/common:constants",
     "//chrome/common/net",
     "//chrome/common/safe_browsing:proto",
     "//chrome/installer/util",
     "//components/cloud_devices/common",
     "//components/content_settings/core/common",
     "//components/json_schema",
     "//components/metrics",
     "//components/policy:policy_component_common",
     "//components/translate/core/common",
     "//components/variations",
     "//content/public/common",
     "//crypto",
-    "//extensions:extensions_resources",
-    "//extensions/strings",
+    "//extensions/common:common_constants",
     "//media/cast:net",
     "//net",
     "//skia",
     "//third_party/icu",
     "//third_party/libxml",
     "//third_party/sqlite",
     "//third_party/zlib:zip",
     "//ui/resources:resources",
     "//url",
   ]
@@ skipping 22 matching lines @@
   if (enable_extensions) {
     sources += rebase_path(
         gypi_values.chrome_common_extensions_sources,
         ".", "//chrome")
     deps += [
       "//device/bluetooth",  # TODO(thestig) Still needed? Not in gyp version.
       "//device/usb",
       "//chrome/common/extensions/api",
       "//extensions/common",
       "//extensions/common/api",
+      "//extensions:extensions_resources",
+      "//extensions/strings",
     ]
   }
 
   if (is_win || is_mac) {
     sources += rebase_path(
         gypi_values.chrome_common_win_mac_sources,
         ".", "//chrome")
     if (use_openssl) {
       sources -= [
         "extensions/api/networking_private/networking_private_crypto_nss.cc",
@@ skipping 162 matching lines @@
       #'../components/nacl.gyp:nacl_switches',  TODO(GYP)
     ]
   }
 }
 
 source_set("test_support") {
   testonly = true
   visibility = [ "//chrome/test:test_support" ]
 
   sources = [
-    "extensions/extension_test_util.cc",
-    "extensions/extension_test_util.h",
   ]
 
   deps = [
     ":common",
     "//base",
     "//testing/gtest",
   ]
 
   if (is_win || is_mac) {
     sources += [
       "media_galleries/picasa_test_util.cc",
       "media_galleries/picasa_test_util.h",
       "media_galleries/pmp_test_util.cc",
       "media_galleries/pmp_test_util.h",
     ]
   }
 
+  if (enable_extensions) {
+    sources += [
+      "extensions/extension_test_util.cc",
+      "extensions/extension_test_util.h",
+    ]
+  }
+
 }