Highlight row (instead of ripple) when come from search.

- Moved HighlightableAdapter to its own class
- Replaced ripple with blue background
- Bluebackground only stays for 5 seconds. After that it's replaced by
  ?attr/selectableBackground

Misc fixes.

- Fix NPE in UserSettings
- Update char limit on a new string

Change-Id: I4687e54e71fd7b9243f520b7630563df58be23d4
Fixes: 71715698
Fixes: 72761974
Test: robotests

tests/unit/src/com/android/settings/SettingsPreferenceFragmentTest.java

@@ -1,70 +0,0 @@
-package com.android.settings;
-
-import static com.google.common.truth.Truth.assertThat;
-
-import android.app.Instrumentation;
-import android.content.Context;
-import android.content.Intent;
-import android.os.Bundle;
-import android.support.test.InstrumentationRegistry;
-import android.support.test.filters.SmallTest;
-import android.support.test.runner.AndroidJUnit4;
-import android.support.v7.preference.Preference;
-import android.support.v7.preference.PreferenceGroupAdapter;
-
-import com.android.settings.accessibility.AccessibilitySettings;
-
-import org.junit.Before;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-@RunWith(AndroidJUnit4.class)
-@SmallTest
-public class SettingsPreferenceFragmentTest {
-
-    private Instrumentation mInstrumentation;
-    private Context mTargetContext;
-
-    @Before
-    public void setUp() throws Exception {
-        mInstrumentation = InstrumentationRegistry.getInstrumentation();
-        mTargetContext = mInstrumentation.getTargetContext();
-    }
-
-    @Test
-    public void testHighlightCaptions() throws InterruptedException {
-        final String prefKey = "captioning_preference_screen";
-        Bundle args = new Bundle();
-        args.putString(SettingsActivity.EXTRA_FRAGMENT_ARG_KEY, prefKey);
-
-        Intent intent = new Intent(Intent.ACTION_MAIN);
-        intent.setClass(mTargetContext, SubSettings.class);
-        intent.putExtra(SettingsActivity.EXTRA_SHOW_FRAGMENT,
-                "com.android.settings.accessibility.AccessibilitySettings");
-        intent.putExtra(SettingsActivity.EXTRA_SHOW_FRAGMENT_ARGUMENTS, args);
-
-        SettingsActivity activity  = (SettingsActivity) mInstrumentation.startActivitySync(intent);
-        AccessibilitySettings fragment = (AccessibilitySettings)
-                activity.getFragmentManager().getFragments().get(0);
-
-        // Allow time for highlight from post-delay.
-        Thread.sleep(SettingsPreferenceFragment.DELAY_HIGHLIGHT_DURATION_MILLIS);
-        if (!fragment.mPreferenceHighlighted) {
-            Thread.sleep(SettingsPreferenceFragment.DELAY_HIGHLIGHT_DURATION_MILLIS);
-        }
-
-        int prefPosition = -1;
-        PreferenceGroupAdapter adapter = (PreferenceGroupAdapter)
-                fragment.getListView().getAdapter();
-        for (int n = 0, count = adapter.getItemCount(); n < count; n++) {
-            final Preference preference = adapter.getItem(n);
-            final String preferenceKey = preference.getKey();
-            if (preferenceKey.equals(prefKey)) {
-                prefPosition = n;
-                break;
-            }
-        }
-
-        assertThat(fragment.mAdapter.initialHighlightedPosition).isEqualTo(prefPosition);
-    }
-}