GCC: use wtf_size_t on WTF::Vector cross thread copier.

Another regression in GCC build caused by the introduction of wtf_size_t on
WTF::Vector in the commit 9d0fd86cf833 "Introduce wtf_size_t which is typedef
for uint32_t".

In this case, it failed because the WTF::CrossThreadCopier structs for vector
were still using size_ instead of wtf_size_t.

Bug: 819294
Change-Id: I62811a58218696f5c3bd409132b44954ff682a40
Reviewed-on: https://chromium-review.googlesource.com/1155110
Reviewed-by: Dave Tapuska <dtapuska@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Dave Tapuska <dtapuska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579112}
1 file changed