Prevent early recent trimming of distinct documents.

Prevent early trimming of documents with distinct
intents. Otherwise when launching a document
from a given activity, existing recent entries
will always be pruned even if they are distinct
documents. We don't have to worry about overflowing
recents, a seperate codepath (from addLocked)
takes care of second pass trimming when we have
exceeded our total max recents.

Bug: 25460953
Change-Id: I71f8c3d46570df2c999f0d986e05515074e0a098

services/core/java/com/android/server/am/RecentTasks.java

@@ -462,10 +462,12 @@ class RecentTasks extends ArrayList<TaskRecord> {
                     final boolean sameActivity = task.realActivity != null
                             && tr.realActivity != null
                             && task.realActivity.equals(tr.realActivity);
-                    if (!sameActivity) {
+                    // If the document is open in another app or is not the same
+                    // document, we don't need to trim it.
+                    if (!sameActivity || !sameIntent) {
                         continue;
-                    }
-                    if (maxRecents > 0 && !doTrim) {
+                    // Otherwise only trim if we are over our max recents for this task
+                    } else if (maxRecents > 0 && !doTrim) {
                         --maxRecents;
                         continue;
                     }