Fix Mac sandbox meta data access (reland)

Fix Mac sandbox meta data access (reland)

We currently allow all metadata access due to
https://codereview.chromium.org/10539009/ made the for loop comparison
in Sandbox::AllowMetadataForPath() always false, when we actually only
want to allow access to the path and all its parent path until root.

Turn the for loop to a do/while loop instead as it's a better fit, also
add a test case for Sandbox::AllowMetadataForPath().

We also need file read meta data access to all the .dylibs we linked to.

It should only affect component builds on OS X 10.6 and utility process
as no other process is using this mechanism.

BUG=403801
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=289738

[Jiang Jiang, 2014-08-14 17:04:36]

Any of you has better idea of how to test it further on 10.6 component builds?

It works for me locally and I don't see any trybot to test it.

[Nico, 2014-08-14 17:42:08]

Since this only makes the sandbox larger (compared the the first, already
approved version of this patch) in component builds, this lgtm

[Nico, 2014-08-14 17:42:39]

(ps: for relanding cls, it's good practice to upload the original change as
patchset 1, and the fixed patchset as patchset 2, then it's easier to see what
was changed)

[Avi (use Gerrit), 2014-08-14 17:47:50]

slgtm

[Jiang Jiang, 2014-08-14 19:01:20]

The CQ bit was checked by jiangj@opera.com

[commit-bot: I haz the power, 2014-08-14 19:03:58]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/jiangj@opera.com/469383002/20001

[commit-bot: I haz the power, 2014-08-15 01:10:33]

Committed patchset #2 (20001) as 289738

[adamk, 2014-08-15 15:38:33]

A revert of this CL (patchset #2) has been created in
https://codereview.chromium.org/470693004/ by adamk@chromium.org.

The reason for reverting is: Caused GPU crashes on Mac10.6 Blink layout tests
running with component=shared_library..

[Greg K, 2015-06-15 23:15:44]

kerrnel@chromium.org changed reviewers:
- avi@chromium.org, jeremy@chromium.org, thakis@chromium.org

[Greg K, 2015-06-15 23:16:44]

On 2014/08/15 15:38:33, adamk wrote:
> A revert of this CL (patchset #2) has been created in
> https://codereview.chromium.org/470693004/ by mailto:adamk@chromium.org.
> 
> The reason for reverting is: Caused GPU crashes on Mac10.6 Blink layout tests
> running with component=shared_library..

Woops, I meant to change the bug and accidentally changed this CL.