Incremental linking setup for GN Windows build.

Incremental linking setup for GN Windows build.

Makes chrome.dll on Windows not use incremental linking since the ilk files get too large.

This refactors the incremental linking configuration to make it easier to change the default.

BUG=

Committed: https://crrev.com/8900cf9444fc3e0adf6728926c96337ccadc9674
Cr-Commit-Position: refs/heads/master@{#321585}

[brettw, 2015-03-19 23:05:39]

brettw@chromium.org changed reviewers:
+ dpranke@chromium.org

[Dirk Pranke, 2015-03-19 23:15:54]

lgtm

[brettw, 2015-03-20 16:55:46]

The CQ bit was checked by brettw@chromium.org

[brettw, 2015-03-20 16:55:46]

The patchset sent to the CQ was uploaded after l-g-t-m from dpranke@chromium.org
Link to the patchset: https://codereview.chromium.org/1019353004/#ps40001
(title: "symbol level")

[commit-bot: I haz the power, 2015-03-20 16:56:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1019353004/40001

[commit-bot: I haz the power, 2015-03-20 17:08:32]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-03-20 17:09:13]

Patchset 3 (id:??) landed as
https://crrev.com/8900cf9444fc3e0adf6728926c96337ccadc9674
Cr-Commit-Position: refs/heads/master@{#321585}