Convert MakeWebEvent parameter types

The parameter types are changed from pointer types to const reference types,
for the purpose of reducing the need for conversions and const_cast at call
sites.

Committed: https://crrev.com/5f6a162270d0ca56437ea78353e32ab40b060122
Cr-Commit-Position: refs/heads/master@{#305444}

[Andre, 2014-11-22 00:06:50]

Patchset #1 (id:1) has been deleted

[Andre, 2014-11-22 00:08:25]

andresantoso@chromium.org changed reviewers:
+ sadrul@chromium.org

[Andre, 2014-11-22 00:08:25]

Sadrul PTAL.
As discussed in https://codereview.chromium.org/739993002/.

[sadrul, 2014-11-24 06:16:05]

Thanks! LGTM

[Andre, 2014-11-24 16:36:32]

The CQ bit was checked by andresantoso@chromium.org

[commit-bot: I haz the power, 2014-11-24 16:37:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/740653006/20001

[commit-bot: I haz the power, 2014-11-24 17:49:36]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2014-11-24 17:52:32]

Patchset 1 (id:??) landed as
https://crrev.com/5f6a162270d0ca56437ea78353e32ab40b060122
Cr-Commit-Position: refs/heads/master@{#305444}