GraphicsLayerUpdater shouldn't spend time in malloc

Now that we've made the compositing update faster, the malloc inside these
vectors is showing up on our profile. We can easily remove the malloc by giving
them some inline capacity. They're only ever stored on the stack, so the extra
inline capacity doesn't cost memory in the heap.

In order to make some code in GraphicsLayer work, I needed to make operator==
on vectors work with vectors of different inline capacities.

R=ojan@chromium.org

Review URL: https://codereview.chromium.org/180733008

git-svn-id: svn://svn.chromium.org/blink/trunk@168661 bbb929c8-8fbe-4397-9dbb-9b2b20218538