Revert "Make DreamActivity no history"

This reverts commit f8ebb8da43b7c04a69ec0f7e15f3f99ff9721531.

Reason for revert: b/271833143 - breaks system dream on tablets

Change-Id: I1dc0c018c170061653fa13ef4121be9758a343b8
diff --git a/core/java/android/service/dreams/DreamActivity.java b/core/java/android/service/dreams/DreamActivity.java
index a389223..a2fa139 100644
--- a/core/java/android/service/dreams/DreamActivity.java
+++ b/core/java/android/service/dreams/DreamActivity.java
@@ -58,13 +58,11 @@
             setTitle(title);
         }
 
-        final Object callback = getIntent().getExtras().getBinder(EXTRA_CALLBACK);
-        if (callback instanceof DreamService.DreamActivityCallbacks) {
-            mCallback = (DreamService.DreamActivityCallbacks) callback;
+        final Bundle extras = getIntent().getExtras();
+        mCallback = (DreamService.DreamActivityCallbacks) extras.getBinder(EXTRA_CALLBACK);
+
+        if (mCallback != null) {
             mCallback.onActivityCreated(this);
-        } else {
-            mCallback = null;
-            finishAndRemoveTask();
         }
     }
 
diff --git a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
index 2c69c9a..8619615 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
@@ -1486,7 +1486,7 @@
         a.persistableMode = ActivityInfo.PERSIST_NEVER;
         a.screenOrientation = ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED;
         a.colorMode = ActivityInfo.COLOR_MODE_DEFAULT;
-        a.flags |= ActivityInfo.FLAG_EXCLUDE_FROM_RECENTS | ActivityInfo.FLAG_NO_HISTORY;
+        a.flags |= ActivityInfo.FLAG_EXCLUDE_FROM_RECENTS;
         a.resizeMode = RESIZE_MODE_UNRESIZEABLE;
         a.configChanges = 0xffffffff;