Use custom drawable for Battery saver condition icon.

- Updated condition interface to use Drawable instead of Icon for icons.
- Converted all conditions to return drawable instead of Icon.
- Created a BatterySaverDrawable to draw a static battery saver icon.

Change-Id: Ie964f3439009c7658603a8ff352a05e964a0a795
Fixes: 76168403
Test: robotests

src/com/android/settings/fuelgauge/BatterySaverDrawable.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.fuelgauge;
+
+import android.content.Context;
+import android.graphics.PorterDuff;
+import android.graphics.PorterDuffColorFilter;
+
+import com.android.settingslib.Utils;
+import com.android.settingslib.graph.BatteryMeterDrawableBase;
+
+/**
+ * Drawable that shows a static battery saver icon - a full battery symbol and a plus sign.
+ */
+public class BatterySaverDrawable extends BatteryMeterDrawableBase {
+
+    private static final int MAX_BATTERY = 100;
+
+    public BatterySaverDrawable(Context context, int frameColor) {
+        super(context, frameColor);
+        // Show as full so it's always uniform color
+        setBatteryLevel(MAX_BATTERY);
+        setPowerSave(true);
+        setCharging(false);
+        setPowerSaveAsColorError(false);
+        final int tintColor = Utils.getColorAttr(context, android.R.attr.colorAccent);
+        setColorFilter(new PorterDuffColorFilter(tintColor, PorterDuff.Mode.SRC_IN));
+    }
+}