Update taskbar drag and drop treatment

- Disable the FastBitmapDrawable icon instead of setting it to invisible
- Suspend auto hide during drag and drop (moved to new TaskbarAutoHideSuspendController)

Test: Drag and drop from taskbar and ensure the original icon stays in place but desaturated
Test: Open immersive app, drag and drop from taskbar and ensure taskbar doesn't hide before drop
Fixes: 200816442
Change-Id: I4b895efd043be75e7e7034bd75e751ffdd2cfdd7

quickstep/src/com/android/launcher3/taskbar/TaskbarAutohideSuspendController.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2021 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.taskbar;
+
+import androidx.annotation.IntDef;
+
+import com.android.quickstep.SystemUiProxy;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * Normally Taskbar will auto-hide when entering immersive (fullscreen) apps. This controller allows
+ * us to suspend that behavior in certain cases (e.g. opening a Folder or dragging an icon).
+ */
+public class TaskbarAutohideSuspendController {
+
+    public static final int FLAG_AUTOHIDE_SUSPEND_FULLSCREEN = 1 << 0;
+    public static final int FLAG_AUTOHIDE_SUSPEND_DRAGGING = 1 << 1;
+    @IntDef(flag = true, value = {
+            FLAG_AUTOHIDE_SUSPEND_FULLSCREEN,
+            FLAG_AUTOHIDE_SUSPEND_DRAGGING,
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface AutohideSuspendFlag {}
+
+    private final SystemUiProxy mSystemUiProxy;
+
+    private @AutohideSuspendFlag int mAutohideSuspendFlags = 0;
+
+    public TaskbarAutohideSuspendController(TaskbarActivityContext activity) {
+        mSystemUiProxy = SystemUiProxy.INSTANCE.get(activity);
+    }
+
+    public void onDestroy() {
+        mSystemUiProxy.notifyTaskbarAutohideSuspend(false);
+    }
+
+    /**
+     * Adds or removes the given flag, then notifies system UI proxy whether to suspend auto-hide.
+     */
+    public void updateFlag(@AutohideSuspendFlag int flag, boolean enabled) {
+        if (enabled) {
+            mAutohideSuspendFlags |= flag;
+        } else {
+            mAutohideSuspendFlags &= ~flag;
+        }
+        mSystemUiProxy.notifyTaskbarAutohideSuspend(mAutohideSuspendFlags != 0);
+    }
+}