[Android] Allow setting recently visited search engines as default search engine

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 74e7253a7a3f4a56442b140ab1ca213441e5a86d..75a249be65a8f615ea60a0b9411c8d3a3a37bc17 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
@@ -8,29 +8,22 @@ import android.os.Bundle;
 import android.preference.PreferenceFragment;
 import android.view.LayoutInflater;
 import android.view.View;
-import android.view.View.OnLayoutChangeListener;
 import android.view.ViewGroup;
 import android.widget.ListView;
 
 import org.chromium.base.VisibleForTesting;
-import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
-import org.chromium.chrome.browser.locale.LocaleManager;
 import org.chromium.chrome.browser.search_engines.TemplateUrlService;
 
 /**
 * A preference fragment for selecting a default search engine.
 */
-public class SearchEnginePreference extends PreferenceFragment
-        implements View.OnClickListener, SearchEngineAdapter.SelectSearchEngineCallback,
-                   OnLayoutChangeListener {
+public class SearchEnginePreference
+        extends PreferenceFragment implements SearchEngineAdapter.SelectSearchEngineCallback {
     private ListView mListView;
-    private View mCancelButton;
-    private View mSaveButton;
-    private View mDivider;
 
     private SearchEngineAdapter mSearchEngineAdapter;
-    private int mSelectedIndex;
+    private String mSelectedKeyword;
 
     @VisibleForTesting
     String getValueForTesting() {
@@ -38,9 +31,13 @@ public class SearchEnginePreference extends PreferenceFragment
     }
 
     @VisibleForTesting
-    void setValueForTesting(String value) {
-        mSearchEngineAdapter.setValueForTesting(value);
-        TemplateUrlService.getInstance().setSearchEngine(mSelectedIndex);
+    String setValueForTesting(String value) {
+        return mSearchEngineAdapter.setValueForTesting(value);
+    }
+
+    @VisibleForTesting
+    String getKeywordFromIndexTesting(int index) {
+        return mSearchEngineAdapter.getKeywordFromIndex(index);
     }
 
     @Override
@@ -57,59 +54,13 @@ public class SearchEnginePreference extends PreferenceFragment
         mListView = (ListView) view.findViewById(android.R.id.list);
         mListView.setAdapter(mSearchEngineAdapter);
         mListView.setDivider(null);
-        mListView.addOnLayoutChangeListener(this);
-        mCancelButton = view.findViewById(R.id.cancel_button);
-        mCancelButton.setOnClickListener(this);
-        mSaveButton = view.findViewById(R.id.save_button);
-        mSaveButton.setOnClickListener(this);
-        mDivider = view.findViewById(R.id.bottom_shadow);
         return view;
     }
 
     @Override
-    public void onActivityCreated(Bundle savedInstanceState) {
-        super.onActivityCreated(savedInstanceState);
-    }
-
-    @Override
-    public void onClick(View v) {
-        if (v == mCancelButton) {
-            getActivity().finish();
-        } else if (v == mSaveButton) {
-            TemplateUrlService.getInstance().setSearchEngine(mSelectedIndex);
-            // If the user has manually set the default search engine, disable auto switching.
-            boolean manualSwitch = mSelectedIndex == mSearchEngineAdapter
-                    .getInitialSearchEnginePosition();
-            if (manualSwitch) {
-                RecordUserAction.record("SearchEngine_ManualChange");
-                LocaleManager.getInstance().setSearchEngineAutoSwitch(false);
-            }
-            getActivity().finish();
-        }
-    }
-
-    @Override
-    public void currentSearchEngineDetermined(int selectedIndex) {
-        mSelectedIndex = selectedIndex;
-    }
-
-    /**
-     * Displays the divider if the Listview is longer than its viewport.
-     */
-    public void updateBottombarDivider() {
-        if (mListView.getLastVisiblePosition() == mSearchEngineAdapter.getCount() - 1) {
-            mDivider.setVisibility(View.INVISIBLE);
-        } else {
-            mDivider.setVisibility(View.VISIBLE);
-        }
-    }
-
-    @Override
-    public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft,
-            int oldTop, int oldRight, int oldBottom) {
-        if (v == mListView) {
-            updateBottombarDivider();
-        }
+    public void currentSearchEngineDetermined(String selectedKeyword) {
+        mSelectedKeyword = selectedKeyword;
+        TemplateUrlService.getInstance().setSearchEngine(mSelectedKeyword);
     }
 
     @Override