Refactor Hydrogen environment liveness analysis into an HPhase.

Refactor Hydrogen environment liveness analysis into an HPhase.
    
Rename EnvironmentSlotLivenessAnalyzer to HEnvironmentLivenessAnalysisPhase,
following naming scheme suggested by danno@chromium.org in
https://codereview.chromium.org/17458002
    
The environment slot liveness analysis now uses the phase zone for
all its allocations.
    
Depends on https://codereview.chromium.org/18034003

R=danno@chromium.org
BUG=

Committed: https://code.google.com/p/v8/source/detail?r=15356

[danno, 2013-06-24 12:11:21]

https://codereview.chromium.org/17587008/diff/1/src/hydrogen-environment-live...
File src/hydrogen-environment-liveness.cc (right):

https://codereview.chromium.org/17587008/diff/1/src/hydrogen-environment-live...
src/hydrogen-environment-liveness.cc:38: Zone* phase_zone)
This should take an CompilationInfo rather than a zone, just like GVN. Also,
should't you refactor into a common base class to share the phase_zone_scope_
machinery before you port over too many of these?

[Benedikt Meurer, 2013-06-24 12:18:28]

https://codereview.chromium.org/17587008/diff/1/src/hydrogen-environment-live...
File src/hydrogen-environment-liveness.cc (right):

https://codereview.chromium.org/17587008/diff/1/src/hydrogen-environment-live...
src/hydrogen-environment-liveness.cc:38: Zone* phase_zone)
On 2013/06/24 12:11:21, danno wrote:
> This should take an CompilationInfo rather than a zone, just like GVN. Also,
> should't you refactor into a common base class to share the phase_zone_scope_
> machinery before you port over too many of these?

Separate CL, see https://codereview.chromium.org/17572011/
I can rebase this one on 17572011 and subclass HPhase. You said you wanted a
small patch with only one class adjusted, that's why I did it this way. :-)

[danno, 2013-06-24 12:25:56]

That's fine, but it's sometimes useful to include dependencies in the comment
(e.g. "Depends on codereview.chromium.org/12345678")  so I know what order you
plan to land the changes is, and indeed rebase it so that I can see the net
effect when you are done.

[Benedikt Meurer, 2013-06-27 09:13:11]

Rebased on https://codereview.chromium.org/18034003

[danno, 2013-06-27 12:59:40]

lgtm

[Benedikt Meurer, 2013-06-27 13:15:17]

Committed patchset #5 manually as r15356 (presubmit successful).