Tweak and repurpose code caching options.

Tweak and repurpose code caching options.

- Removed lower and upper source size limit for code caching.
- *Small and *Mobile options turn on compression.
- HeuristicsDefault* options cache on first occurrence.
- Recent* options cache on second occurrence within 36 hours.
- Heuristics* options cache on second occurrence within 72 hours.
- Added V8.CodeCacheSizeRatio histogram to track code cache overhead.

BUG=chromium:399580
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=189511

[Yang, 2015-02-04 12:57:27]

yangguo@chromium.org changed reviewers:
+ jochen@chromium.org, vogelheim@google.com

[Yang, 2015-02-04 12:57:27]

Offline discussion concluded that we definitely want to get rid of the upper
size limit and the lower size limit is arbitrary and has no justification for
code caching. Instead of going through renaming those options, I opted for
repurposing them. I filed a bug to clean up those options once we decided on the
best strategy.

[vogelheim, 2015-02-04 12:58:52]

vogelheim@chromium.org changed reviewers:
+ vogelheim@chromium.org
- vogelheim@google.com

[vogelheim, 2015-02-04 13:16:00]

lgtm

[jochen (gone - plz use gerrit), 2015-02-04 13:24:20]

lgtm

[Yang, 2015-02-04 13:25:05]

The CQ bit was checked by yangguo@chromium.org

[commit-bot: I haz the power, 2015-02-04 13:25:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/869513005/1

[commit-bot: I haz the power, 2015-02-04 16:20:52]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=189511