Show a scrim activity if task is not resizable

Add a callback to TaskStackChangeListener which gets fired when the system
might need to inform the user that a specific app might not work in
multi-window.

Use that callback in SysUI to show a translucent activity which scrims the
activity behind to inform that it might not be resizable.

Debounce the information to once per multi-window session, to not make it
annoying.

Introduce launchTaskId to start an activity in an existing task, and protect
that with START_TASKS_FROM_RECENTS permission.

Bug: 27327287
Bug: 27431869
Change-Id: I89e8d653872ab01ba3c1e252b426e5481da0e6ca

4 files changed, 40 insertions, 1 deletions

diff --git a/core/java/android/app/ActivityOptions.java b/core/java/android/app/ActivityOptions.java
index 167e6cbeb84f..284679838213 100644
--- a/core/java/android/app/ActivityOptions.java
+++ b/core/java/android/app/ActivityOptions.java
@@ -154,6 +154,12 @@ public class ActivityOptions {
     private static final String KEY_LAUNCH_STACK_ID = "android.activity.launchStackId";
 
     /**
+     * The task id the activity should be launched into.
+     * @hide
+     */
+    private static final String KEY_LAUNCH_TASK_ID = "android.activity.launchTaskId";
+
+    /**
      * Where the docked stack should be positioned.
      * @hide
      */
@@ -224,6 +230,7 @@ public class ActivityOptions {
     private int mExitCoordinatorIndex;
     private PendingIntent mUsageTimeReport;
     private int mLaunchStackId = INVALID_STACK_ID;
+    private int mLaunchTaskId = -1;
     private int mDockCreateMode = DOCKED_STACK_CREATE_MODE_TOP_OR_LEFT;
     private AppTransitionAnimationSpec mAnimSpecs[];
 
@@ -766,6 +773,7 @@ public class ActivityOptions {
                 break;
         }
         mLaunchStackId = opts.getInt(KEY_LAUNCH_STACK_ID, INVALID_STACK_ID);
+        mLaunchTaskId = opts.getInt(KEY_LAUNCH_TASK_ID, -1);
         mDockCreateMode = opts.getInt(KEY_DOCK_CREATE_MODE, DOCKED_STACK_CREATE_MODE_TOP_OR_LEFT);
         if (opts.containsKey(KEY_ANIM_SPECS)) {
             Parcelable[] specs = opts.getParcelableArray(KEY_ANIM_SPECS);
@@ -927,6 +935,21 @@ public class ActivityOptions {
         mLaunchStackId = launchStackId;
     }
 
+    /**
+     * Sets the task the activity will be launched in.
+     * @hide
+     */
+    public void setLaunchTaskId(int taskId) {
+        mLaunchTaskId = taskId;
+    }
+
+    /**
+     * @hide
+     */
+    public int getLaunchTaskId() {
+        return mLaunchTaskId;
+    }
+
     /** @hide */
     public int getDockCreateMode() {
         return mDockCreateMode;
@@ -1079,6 +1102,7 @@ public class ActivityOptions {
                 break;
         }
         b.putInt(KEY_LAUNCH_STACK_ID, mLaunchStackId);
+        b.putInt(KEY_LAUNCH_TASK_ID, mLaunchTaskId);
         b.putInt(KEY_DOCK_CREATE_MODE, mDockCreateMode);
         if (mAnimSpecs != null) {
             b.putParcelableArray(KEY_ANIM_SPECS, mAnimSpecs);
diff --git a/core/java/android/app/ContextImpl.java b/core/java/android/app/ContextImpl.java
index 63a68294fb3d..d28f1fbf0744 100644
--- a/core/java/android/app/ContextImpl.java
+++ b/core/java/android/app/ContextImpl.java
@@ -803,7 +803,12 @@ class ContextImpl extends Context {
     @Override
     public void startActivity(Intent intent, Bundle options) {
         warnIfCallingFromSystemProcess();
-        if ((intent.getFlags()&Intent.FLAG_ACTIVITY_NEW_TASK) == 0) {
+
+        // Calling start activity from outside an activity without FLAG_ACTIVITY_NEW_TASK is
+        // generally not allowed, except if the caller specifies the task id the activity should
+        // be launched in.
+        if ((intent.getFlags()&Intent.FLAG_ACTIVITY_NEW_TASK) == 0
+                && options != null && ActivityOptions.fromBundle(options).getLaunchTaskId() == -1) {
             throw new AndroidRuntimeException(
                     "Calling startActivity() from outside of an Activity "
                     + " context requires the FLAG_ACTIVITY_NEW_TASK flag."
diff --git a/core/java/android/app/ITaskStackListener.aidl b/core/java/android/app/ITaskStackListener.aidl
index 643255822cb9..fa6752943e75 100644
--- a/core/java/android/app/ITaskStackListener.aidl
+++ b/core/java/android/app/ITaskStackListener.aidl
@@ -35,4 +35,9 @@ oneway interface ITaskStackListener {
      * Called whenever the pinned stack is done animating a resize.
      */
     void onPinnedStackAnimationEnded();
+
+    /**
+     * Called when we launched an activity that we forced to be resizable.
+     */
+    void onActivityForcedResizable(String packageName, int taskId);
 }
diff --git a/core/java/com/android/internal/statusbar/IStatusBar.aidl b/core/java/com/android/internal/statusbar/IStatusBar.aidl
index b243cac29182..9e5c2383c008 100644
--- a/core/java/com/android/internal/statusbar/IStatusBar.aidl
+++ b/core/java/com/android/internal/statusbar/IStatusBar.aidl
@@ -88,6 +88,11 @@ oneway interface IStatusBar
      */
     void appTransitionStarting(long statusBarAnimationsStartTime, long statusBarAnimationsDuration);
 
+    /**
+     * Notifies the status bar that an app transition is done.
+     */
+    void appTransitionFinished();
+
     void showAssistDisclosure();
     void startAssist(in Bundle args);