Updating Robolectric tests

> Adding multi-thread support
> Simulating actual loader loading flow
> Moving some android tests to robolectic

Change-Id: Ie17a448f20e8a4b1f18ecc33d22054bbf9e18729
diff --git a/robolectric_tests/src/com/android/launcher3/shadows/LShadowBitmap.java b/robolectric_tests/src/com/android/launcher3/shadows/LShadowBitmap.java
new file mode 100644
index 0000000..abd90bb
--- /dev/null
+++ b/robolectric_tests/src/com/android/launcher3/shadows/LShadowBitmap.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2019 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.launcher3.shadows;
+
+import android.graphics.Bitmap;
+import android.graphics.Paint;
+
+import org.robolectric.annotation.Implementation;
+import org.robolectric.annotation.Implements;
+import org.robolectric.shadows.ShadowBitmap;
+
+/**
+ * Extension of {@link ShadowBitmap} with missing shadow methods
+ */
+@Implements(value = Bitmap.class)
+public class LShadowBitmap extends ShadowBitmap {
+
+    @Implementation
+    protected Bitmap extractAlpha(Paint paint, int[] offsetXY) {
+        return extractAlpha();
+    }
+}