Oilpan: Replace Node* pointers with Member<Node>s

Oilpan: Replace Node* pointers with Member<Node>s

- Make SelectorCheckerContext STACK_ALLOCATED.
- Make FocusCandidate STACK_ALLOCATED.
- Make TreeBoundaryCrossingRuleSetMap a hash map from Member<Node> to Member<CSSStyleSheetRuleSubSet>. This hash map doesn't need to be weak.

BUG=340522
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=179087

[haraken, 2014-07-28 20:05:37]

PTAL

[tkent, 2014-07-28 23:19:16]

lgtm

[commit-bot: I haz the power, 2014-07-28 23:20:10]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/haraken@chromium.org/423953003/20001

[commit-bot: I haz the power, 2014-07-28 23:59:25]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/19333)

[commit-bot: I haz the power, 2014-07-29 01:05:18]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-07-29 01:05:19]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/19339)

[haraken, 2014-07-29 01:07:48]

The CQ bit was checked by haraken@chromium.org

[commit-bot: I haz the power, 2014-07-29 01:08:31]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/haraken@chromium.org/423953003/20001

[commit-bot: I haz the power, 2014-07-29 01:58:07]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/19353)

[commit-bot: I haz the power, 2014-07-29 02:33:05]

Change committed as 179087