[small-vector] Hard-crash on failed allocation

.. of the backing store, instead of continuing and silently attempting
to deref nullptr.

Bug: chromium:1198657
Change-Id: I82e51abc4d2f9dfe0de596b082a6f78089af7df8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2824438Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73949}

src/base/small-vector.h

@@ -154,6 +154,13 @@ class SmallVector {
         base::bits::RoundUpToPowerOfTwo(std::max(min_capacity, 2 * capacity()));
     T* new_storage =
         reinterpret_cast<T*>(base::Malloc(sizeof(T) * new_capacity));
+    if (new_storage == nullptr) {
+      // Should be: V8::FatalProcessOutOfMemory, but we don't include V8 from
+      // base. The message is intentionally the same as FatalProcessOutOfMemory
+      // since that will help fuzzers and chromecrash to categorize such
+      // crashes appropriately.
+      FATAL("Fatal process out of memory: base::SmallVector::Grow");
+    }
     base::Memcpy(new_storage, begin_, sizeof(T) * in_use);
     if (is_big()) base::Free(begin_);
     begin_ = new_storage;