X87: Remove code object from StackHandler.

X87: Remove code object from StackHandler.

port e0aa8ebf933b4c659e1c4a01ba244c5de452ff1c (r27103).

original commit message:

  This reduces the size of the StackHandler by one word. We no longer
  need to keep track of the code object, as the stack walk finds it.

BUG=
R=weiliang.lin@intel.com

Committed: https://crrev.com/289ee153072a23f814eb00b96b6eac511dab0041
Cr-Commit-Position: refs/heads/master@{#27353}

[chunyang.dai, 2015-03-23 08:03:06]

PTAL.

[chunyang.dai, 2015-03-23 08:03:25]

chunyang.dai@intel.com changed reviewers:
+ weiliang.lin@intel.com

[Weiliang, 2015-03-23 08:19:19]

The CQ bit was checked by weiliang.lin@intel.com

[Weiliang, 2015-03-23 08:19:20]

lgtm

[commit-bot: I haz the power, 2015-03-23 08:19:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1022403002/1

[commit-bot: I haz the power, 2015-03-23 08:27:27]

Patchset 1 (id:??) landed as
https://crrev.com/289ee153072a23f814eb00b96b6eac511dab0041
Cr-Commit-Position: refs/heads/master@{#27353}

[chunyang.dai, 2015-03-23 08:27:29]

Committed patchset #1 (id:1) manually as
289ee153072a23f814eb00b96b6eac511dab0041 (presubmit successful).