Remove divider lines from all PreferenceFragments.

(this is partially revert of ag/I0ce486f7ac6)

- Only draw divider lines on top of PreferenceCategory and
  FooterPreference

Bug: 33601143
Test: make RunSettingsRoboTests
Change-Id: I26146dcae1603dc807e54ea431910685107be94c

src/com/android/settings/dashboard/DashboardFragment.java

@@ -17,9 +17,6 @@ package com.android.settings.dashboard;
 
 import android.app.Activity;
 import android.content.Context;
-import android.graphics.Color;
-import android.graphics.drawable.ColorDrawable;
-import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.support.annotation.VisibleForTesting;
 import android.support.v7.preference.Preference;
@@ -117,16 +114,6 @@ public abstract class DashboardFragment extends SettingsPreferenceFragment
         refreshAllPreferences(getLogTag());
     }
 
-    @Override
-    public void setDivider(Drawable divider) {
-        if (mDashboardFeatureProvider.isEnabled()) {
-            // Intercept divider and set it transparent so system divider decoration is disabled.
-            super.setDivider(new ColorDrawable(Color.TRANSPARENT));
-        } else {
-            super.setDivider(divider);
-        }
-    }
-
     @Override
     public void onStart() {
         super.onStart();