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

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 636457819df4d695daec3b5c24845e499658847b..80be2c4dda58cea8542419471b2074a4c6bc0425 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -53,6 +53,7 @@
 #include "components/search/search_switches.h"
 #include "components/security_state/switches.h"
 #include "components/signin/core/common/signin_switches.h"
+#include "components/spellcheck/common/spellcheck_switches.h"
 #include "components/ssl_config/ssl_config_switches.h"
 #include "components/sync_driver/sync_driver_switches.h"
 #include "components/tracing/common/tracing_switches.h"
@@ -830,7 +831,7 @@ const FeatureEntry kFeatureEntries[] = {
 #if defined(ENABLE_SPELLCHECK) && defined(OS_ANDROID)
     {"enable-android-spellchecker", IDS_OPTIONS_ENABLE_SPELLCHECK,
      IDS_OPTIONS_ENABLE_ANDROID_SPELLCHECKER_DESCRIPTION, kOsAndroid,
-     SINGLE_VALUE_TYPE(switches::kEnableAndroidSpellChecker)},
+     SINGLE_VALUE_TYPE(spellcheck::switches::kEnableAndroidSpellChecker)},
 #endif
     {"enable-scroll-prediction", IDS_FLAGS_SCROLL_PREDICTION_NAME,
      IDS_FLAGS_SCROLL_PREDICTION_DESCRIPTION, kOsDesktop,
@@ -1220,7 +1221,8 @@ const FeatureEntry kFeatureEntries[] = {
     {"enable-spelling-feedback-field-trial",
      IDS_FLAGS_SPELLING_FEEDBACK_FIELD_TRIAL_NAME,
      IDS_FLAGS_SPELLING_FEEDBACK_FIELD_TRIAL_DESCRIPTION, kOsAll,
-     SINGLE_VALUE_TYPE(switches::kEnableSpellingFeedbackFieldTrial)},
+     SINGLE_VALUE_TYPE(
+         spellcheck::switches::kEnableSpellingFeedbackFieldTrial)},
 #endif
     {"enable-webgl-draft-extensions", IDS_FLAGS_WEBGL_DRAFT_EXTENSIONS_NAME,
      IDS_FLAGS_WEBGL_DRAFT_EXTENSIONS_DESCRIPTION, kOsAll,