Componentize spellcheck [1]: create component and move switches there.

chrome/renderer/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/features.gni")
 import("//tools/grit/grit_rule.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("../chrome_renderer.gypi") ],
                           "scope",
@@ skipping 138 matching lines @@
   }
   if (enable_extensions && enable_webrtc) {
     sources +=
         rebase_path(gypi_values.chrome_renderer_webrtc_extensions_sources,
                     ".",
                     "..")
   }
   if (enable_spellcheck) {
     sources +=
         rebase_path(gypi_values.chrome_renderer_spellchecker_sources, ".", "..")
+    deps += [ "//components/spellcheck/common:common" ]
+
     if (!is_android) {
       deps += [ "//third_party/hunspell" ]
     }
   }
   if (!use_browser_spellchecker) {
     sources -= [
       "spellchecker/platform_spelling_engine.cc",
       "spellchecker/platform_spelling_engine.h",
     ]
   }
@@ skipping 55 matching lines @@
     ]
   }
 
   if (is_android) {
     sources -= [
       "safe_browsing/mock_feature_extractor_clock.cc",
       "safe_browsing/mock_feature_extractor_clock.h",
     ]
   }
 }