Merge changes Ie5b66d6c,Ia1004ca6

* changes:
  Revert "Otapreopt: Work around bug 38186355"
  Clean up possible null dereference warning.
diff --git a/cmds/installd/CacheTracker.cpp b/cmds/installd/CacheTracker.cpp
index e293948..3eb39b9 100644
--- a/cmds/installd/CacheTracker.cpp
+++ b/cmds/installd/CacheTracker.cpp
@@ -148,6 +148,7 @@
         }
 
         // Bubble up modified time to parent
+        CHECK(p != nullptr);
         switch (p->fts_info) {
         case FTS_DP:
         case FTS_DEFAULT:
diff --git a/cmds/installd/otapreopt.cpp b/cmds/installd/otapreopt.cpp
index 68cb0d7..99ff20d 100644
--- a/cmds/installd/otapreopt.cpp
+++ b/cmds/installd/otapreopt.cpp
@@ -753,10 +753,6 @@
     }
 
     static const char* ParseNull(const char* arg) {
-        // b/38186355. Revert soon.
-        if (strcmp(arg, "!null") == 0) {
-            return nullptr;
-        }
         return (strcmp(arg, "!") == 0) ? nullptr : arg;
     }