Exclude spellcheck related code properly on android/ios which doesn't have spellchecker

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 3b55164eea31eee2a3a78e41ce150602c3634bb2..f15cd23918eb6f68eaa208ce71cf9a0b15e3daa3 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -858,6 +858,7 @@ const Experiment kExperiments[] = {
     kOsDesktop,
     SINGLE_VALUE_TYPE(switches::kSilentDebuggerExtensionAPI)
   },
+#if defined(ENABLE_SPELLCHECK)
   {
     "spellcheck-autocorrect",
     IDS_FLAGS_SPELLCHECK_AUTOCORRECT,
@@ -865,6 +866,7 @@ const Experiment kExperiments[] = {
     kOsWin | kOsLinux | kOsCrOS,
     SINGLE_VALUE_TYPE(switches::kEnableSpellingAutoCorrect)
   },
+#endif
   {
     "enable-scroll-prediction",
     IDS_FLAGS_ENABLE_SCROLL_PREDICTION_NAME,
@@ -1418,6 +1420,7 @@ const Experiment kExperiments[] = {
     MULTI_VALUE_TYPE(kTabCaptureDownscaleQualityChoices)
   },
 #endif
+#if defined(ENABLE_SPELLCHECK)
   {
     "enable-spelling-feedback-field-trial",
     IDS_FLAGS_ENABLE_SPELLING_FEEDBACK_FIELD_TRIAL_NAME,
@@ -1425,6 +1428,7 @@ const Experiment kExperiments[] = {
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kEnableSpellingFeedbackFieldTrial)
   },
+#endif
   {
     "enable-webgl-draft-extensions",
     IDS_FLAGS_ENABLE_WEBGL_DRAFT_EXTENSIONS_NAME,