[layoutng] Make DerivedGeometry use partition alloc

R=ikilpatrick@chromium.org,eae@chromium.org

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I4d70f5a3e22a32ee2c9c261b731fd7afafe7ce0f
Reviewed-on: https://chromium-review.googlesource.com/1227252Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591533}

third_party/blink/renderer/core/layout/ng/exclusions/ng_exclusion_space.h

@@ -190,6 +190,9 @@ class CORE_EXPORT NGExclusionSpaceInternal {
   // we trigger a (rare) re-layout case will we need to rebuild the
   // derived_geometry_ data-structure.
   struct DerivedGeometry {
+    USING_FAST_MALLOC(DerivedGeometry);
+
+   public:
     DerivedGeometry();
     DerivedGeometry(DerivedGeometry&& o) noexcept = default;