Changing the state UI logic for normal build and quickStep build

> Creating ShareHandlers for managing UI
> In normal build, hotseat is hidden in overview, while in QuickStepBuild, it is visible

Change-Id: I5f8d35c75b861d912d93fce186b5dd74106184c3

quickstep/src/com/android/launcher3/uioverrides/RecentsViewStateController.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2017 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.uioverrides;
+
+import static com.android.launcher3.WorkspaceStateTransitionAnimation.NO_ANIM_PROPERTY_SETTER;
+
+import android.animation.AnimatorSet;
+
+import com.android.launcher3.Launcher;
+import com.android.launcher3.LauncherState;
+import com.android.launcher3.LauncherStateManager.AnimationConfig;
+import com.android.launcher3.LauncherStateManager.StateHandler;
+import com.android.launcher3.WorkspaceStateTransitionAnimation.AnimatedPropertySetter;
+import com.android.launcher3.WorkspaceStateTransitionAnimation.PropertySetter;
+import com.android.launcher3.anim.AnimationLayerSet;
+
+public class RecentsViewStateController implements StateHandler {
+
+    private final Launcher mLauncher;
+
+    public RecentsViewStateController(Launcher launcher) {
+        mLauncher = launcher;
+    }
+
+    @Override
+    public void setState(LauncherState state) {
+        setState(state, NO_ANIM_PROPERTY_SETTER);
+    }
+
+    @Override
+    public void setStateWithAnimation(LauncherState toState, AnimationLayerSet layerViews,
+            AnimatorSet anim, AnimationConfig config) {
+        setState(toState, new AnimatedPropertySetter(config.duration, layerViews, anim));
+    }
+
+    private void setState(LauncherState state, PropertySetter setter) {
+        setter.setViewAlpha(null, mLauncher.getOverviewPanel(),
+                state == LauncherState.OVERVIEW ? 1 : 0);
+    }
+}