Estimate renderer memory usage in MacOS via working set size instead of page file size.

Estimate renderer memory usage in MacOS via working set size instead of page file size.

BUG=v8:1904
TEST=see the bug


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=118477

[ulan, 2012-01-20 14:03:28]

Darin, could you please take a look?

I am asking you because you are an owner of src/webkit.

The existing memory usage estimation counts the whole virtual address space size
including shared/unmapped pages. So it overestimate the actual memory usage,
e.g. immediately after starting the browser, the memory usage estimate is about
800MB. This leads to false positive low-memory notifications and thus to long
pauses in the renderer. This issue only occurs in MacOS.

The proposed estimation is more close to what the chrome task manager reports.

[darin (slow to review), 2012-01-20 18:18:58]

LGTM

[commit-bot: I haz the power, 2012-01-20 18:19:12]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ulan@chromium.org/9138019/1

[commit-bot: I haz the power, 2012-01-20 20:13:42]

Change committed as 118477