Revert "Revert "Fixup app-private dirs that are not writable.""

Fixup non-writable app-private dirs that could have been left around by
an earlier race condition in the setup of the FUSE filesystem.

Bug: 181726193
Bug: 182088154
Test: erase userdata, check Youtube dirs are fixed up correctly

Reason for revert: fixing issue in original CL

Change-Id: Ifacf807f62dec3c9e22b5e5af0f2b00c4423ede4

core/java/android/app/ContextImpl.java

@@ -3273,6 +3273,13 @@ class ContextImpl extends Context {
                     dir = null;
                 }
             }
+            if (dir != null && !dir.canWrite()) {
+                // Older versions of the MediaProvider mainline module had a rare early boot race
+                // condition where app-private dirs could be created with the wrong permissions;
+                // fix this up here. This check should be very fast, because dir.exists() above
+                // will already have loaded the dentry in the cache.
+                sm.fixupAppDir(dir);
+            }
             result[i] = dir;
         }
         return result;