https://developer.apple.com/library/mac/documentation/Performance/Conceptual/ManagingMemory/Articles/AboutMemory.html#//apple_ref/doc/uid/20001880-SW3

R=jochen@chromium.org

Review-Url: https://codereview.chromium.org/2278473002
Cr-Commit-Position: refs/heads/master@{#38877}