Remove code object from StackHandler.

Remove code object from StackHandler.

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.

R=yangguo@chromium.org

Committed: https://crrev.com/e0aa8ebf933b4c659e1c4a01ba244c5de452ff1c
Cr-Commit-Position: refs/heads/master@{#27103}

[Michael Starzinger, 2015-03-06 16:53:54]

I applied the first layer of StackHandler'b'gone and let it soak for a while. I
think after four more applications we should be good. :)

[Yang, 2015-03-10 12:49:26]

lgtm

[Michael Starzinger, 2015-03-10 12:52:08]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-03-10 12:52:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/985803002/1

[commit-bot: I haz the power, 2015-03-10 13:20:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-10 13:20:37]

Patchset 1 (id:??) landed as
https://crrev.com/e0aa8ebf933b4c659e1c4a01ba244c5de452ff1c
Cr-Commit-Position: refs/heads/master@{#27103}