Deprecate SharedPreferences key "bookmark_search_history".

Cleanup code is not necessary anymore as long as the key is not used.

Bug: 1022108
Change-Id: Ia3e6a8f7ec489fcc2e69caa511809a95525af317
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1972783Reviewed-by: Theresa  <twellington@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#725980}

chrome/android/java/src/org/chromium/chrome/browser/bookmarks/BookmarkManager.java

@@ -49,12 +49,6 @@ public class BookmarkManager
     private static final int FAVICON_MAX_CACHE_SIZE_BYTES =
             10 * ConversionUtils.BYTES_PER_MEGABYTE; // 10MB
 
-    /**
-     * This shared preference used to be used to save a list of recent searches. That feature
-     * has been removed, so this string is now used solely to clear the shared preference.
-     */
-    private static final String PREF_SEARCH_HISTORY = "bookmark_search_history";
-
     private static boolean sPreventLoadingForTesting;
 
     private Activity mActivity;
@@ -285,10 +279,6 @@ public class BookmarkManager
         if (!isDialogUi) {
             RecordUserAction.record("MobileBookmarkManagerPageOpen");
         }
-
-        // TODO(twellington): Remove this when Chrome version 59 is a distant memory and users
-        // are unlikely to have the old PREF_SEARCH_HISTORY in shared preferences.
-        ContextUtils.getAppSharedPreferences().edit().remove(PREF_SEARCH_HISTORY).apply();
     }
 
     @Override

chrome/browser/preferences/android/java/src/org/chromium/chrome/browser/preferences/ChromePreferenceKeys.java

@@ -539,6 +539,7 @@ public final class ChromePreferenceKeys {
         // clang-format off
         return Arrays.asList(
                 "allow_low_end_device_ui",
+                "bookmark_search_history",
                 "website_settings_filter",
                 "chrome_modern_design_enabled",
                 "home_page_button_force_enabled",