Add Settings icons needed for theme overlaying.

- Refactor battery icons to remove private attributes to allow them to
be overlayed
- Add drawable icon in settings for back arrow
- Update a few GM2 icons

Bug: 128354921
Test: make; open Settings
Change-Id: I84151a4e7d787381b6c51f02bb45ce5f15fa37a2

src/com/android/settings/fuelgauge/batterytip/tips/EarlyWarningTip.java

@@ -18,6 +18,7 @@ package com.android.settings.fuelgauge.batterytip.tips;
 
 import android.app.settings.SettingsEnums;
 import android.content.Context;
+import android.content.res.ColorStateList;
 import android.os.Parcel;
 
 import com.android.settings.R;
@@ -62,6 +63,13 @@ public class EarlyWarningTip extends BatteryTip {
                 : R.drawable.ic_battery_status_bad_24dp;
     }
 
+    @Override
+    public ColorStateList getIconTint() {
+        return ColorStateList.valueOf(mState == StateType.HANDLED
+                ? R.color.battery_maybe_color_light
+                : R.color.battery_bad_color_light);
+    }
+
     @Override
     public void updateState(BatteryTip tip) {
         final EarlyWarningTip earlyWarningTip = (EarlyWarningTip) tip;