Remove usage of CHECK_NOTNULL

We want to switch to absl logging instead of glog.  gtest and ceres are
going there, and we already have absl as a dependency.  ABSL doesn't
have CHECK_NOTNULL, and we can move things over in an easier to review
fashion.

Change-Id: Ifd9a11ec34a2357cec43f88dba015db9c28ed2cf
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/aos/containers/resizeable_buffer.h b/aos/containers/resizeable_buffer.h
index 664fa2f..1af888d 100644
--- a/aos/containers/resizeable_buffer.h
+++ b/aos/containers/resizeable_buffer.h
@@ -108,7 +108,9 @@
 
   void Allocate(size_t new_capacity) {
     void *const old = storage_.release();
-    storage_.reset(CHECK_NOTNULL(F::Realloc(old, capacity_, new_capacity)));
+    void *new_ptr = F::Realloc(old, capacity_, new_capacity);
+    CHECK(new_ptr != nullptr);
+    storage_.reset(new_ptr);
     capacity_ = new_capacity;
   }