CacheStorage: Pass an error object allocated on heap to WebCallbacks::onError (3)

CacheStorage: Pass an error object allocated on heap to WebCallbacks::onError (3)

This is a preliminary patch to simplify memory management in
CallbackPromiseAdapter. See (1) for details.

(1) Chromium: https://codereview.chromium.org/1152003008
(2) Blink: https://codereview.chromium.org/1155573003
(3) Chromium: THIS PATCH
(4) Blink: https://codereview.chromium.org/1150413004

BUG=494884
TEST=n/a

Committed: https://crrev.com/8772855e3e7efe43cce9fa2e5b0e6dfaa2837bc1
Cr-Commit-Position: refs/heads/master@{#335030}

[nhiroki, 2015-06-17 08:34:35]

Patchset #1 (id:1) has been deleted

[nhiroki, 2015-06-17 08:34:43]

Patchset #1 (id:20001) has been deleted

[jkarlin, 2015-06-17 11:16:44]

jkarlin@chromium.org changed reviewers:
+ jkarlin@chromium.org

[jkarlin, 2015-06-17 11:16:45]

lgtm

[nhiroki, 2015-06-18 12:25:20]

The CQ bit was checked by nhiroki@chromium.org

[commit-bot: I haz the power, 2015-06-18 12:26:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1150333003/40001

[commit-bot: I haz the power, 2015-06-18 13:51:22]

Committed patchset #1 (id:40001)

[commit-bot: I haz the power, 2015-06-18 13:52:12]

Patchset 1 (id:??) landed as
https://crrev.com/8772855e3e7efe43cce9fa2e5b0e6dfaa2837bc1
Cr-Commit-Position: refs/heads/master@{#335030}