Implement search engine auto switch when entering or leaving some locale

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

Index: chrome/android/java/src/org/chromium/chrome/browser/preferences/SearchEnginePreference.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/preferences/SearchEnginePreference.java b/chrome/android/java/src/org/chromium/chrome/browser/preferences/SearchEnginePreference.java
index 9ef7822c1d6f7f5d30a270cc627052c55e6c8892..cd3b75beb91abc05d5068eac85278e67998e4914 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/preferences/SearchEnginePreference.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/preferences/SearchEnginePreference.java
@@ -14,6 +14,7 @@ import android.widget.ListView;
 
 import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.R;
+import org.chromium.chrome.browser.locale.LocaleManager;
 import org.chromium.chrome.browser.search_engines.TemplateUrlService;
 
 /**
@@ -75,6 +76,9 @@ public class SearchEnginePreference extends PreferenceFragment
             getActivity().finish();
         } else if (v == mSaveButton) {
             TemplateUrlService.getInstance().setSearchEngine(mSelectedIndex);
+            // If the user has manually set the default search engine, disable auto switching.
+            LocaleManager.getInstance().setSearchEngineAutoSwitch(
+                    mSelectedIndex == mSearchEngineAdapter.getInitialSearchEnginePosition());
             getActivity().finish();
         }
     }