Move IconCache to SettingsLib(I).

Aim to share IconCache between Settings & TvSettings.

Test: Compiled
Change-Id: Ia7c9807cea587b6d654c80f6dbbf43467f48cc5b

packages/SettingsLib/src/com/android/settingslib/utils/IconCache.java

@@ -0,0 +1,53 @@
+/*
+ * 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.settingslib.utils;
+
+import android.content.Context;
+import android.graphics.drawable.Drawable;
+import android.graphics.drawable.Icon;
+import android.support.annotation.VisibleForTesting;
+import android.support.v4.util.ArrayMap;
+
+
+/**
+ * Icon cache to avoid multiple loads on the same icon.
+ */
+public class IconCache {
+    private final Context mContext;
+    @VisibleForTesting
+    final ArrayMap<Icon, Drawable> mMap = new ArrayMap<>();
+
+    public IconCache(Context context) {
+        mContext = context;
+    }
+
+    public Drawable getIcon(Icon icon) {
+        if (icon == null) {
+            return null;
+        }
+        Drawable drawable = mMap.get(icon);
+        if (drawable == null) {
+            drawable = icon.loadDrawable(mContext);
+            updateIcon(icon, drawable);
+        }
+        return drawable;
+    }
+
+    public void updateIcon(Icon icon, Drawable drawable) {
+        mMap.put(icon, drawable);
+    }
+}

packages/SettingsLib/tests/robotests/src/com/android/settingslib/utils/IconCacheTest.java

@@ -0,0 +1,72 @@
+/*
+ * 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.settingslib.utils;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static junit.framework.Assert.assertTrue;
+
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import android.content.Context;
+import android.graphics.drawable.Drawable;
+import android.graphics.drawable.Icon;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+@RunWith(RobolectricTestRunner.class)
+public class IconCacheTest {
+    private Icon mIcon;
+    private Context mContext;
+    private IconCache mIconCache;
+
+    @Before
+    public void setUp() {
+        mContext = spy(RuntimeEnvironment.application);
+        mIcon = mock(Icon.class);
+        Drawable drawable = mock(Drawable.class);
+        doReturn(drawable).when(mIcon).loadDrawable(mContext);
+        mIconCache = new IconCache(mContext);
+    }
+
+    @Test
+    public void testGetIcon_iconisNull() {
+        assertThat(mIconCache.getIcon(null)).isNull();
+    }
+
+    @Test
+    public void testGetIcon_iconAlreadyLoaded() {
+        mIconCache.getIcon(mIcon);
+        verify(mIcon, times(1)).loadDrawable(mContext);
+        mIconCache.getIcon(mIcon);
+        verify(mIcon, times(1)).loadDrawable(mContext);
+    }
+
+    @Test
+    public void testGetIcon_iconLoadedFirstTime() {
+        mIconCache.getIcon(mIcon);
+        assertTrue(mIconCache.mMap.containsKey(mIcon));
+    }
+}