[SystemWebViewShell] Fix WebViewShell manifest.

[SystemWebViewShell] Fix WebViewShell manifest.

The WebViewShell should not have BaseChromiumApplication as name.
The breaking change was introduced in crrev.com/1402833002, this
patch reverts it.

Note: deriving from BaseChromiumApplication has the effect that
some chromium specific code is initialized that is not normally
initialized in apps.

BUG=
TBR=torne@chromium.org

Committed: https://crrev.com/5f4a677bdba5250ff3ed3fc829975cbe489d3d24
Cr-Commit-Position: refs/heads/master@{#354514}

[timvolodine, 2015-10-16 15:03:33]

timvolodine@chromium.org changed reviewers:
+ torne@chromium.org

[Torne, 2015-10-16 15:07:36]

lgtm

[timvolodine, 2015-10-16 15:10:12]

On 2015/10/16 15:07:36, Torne wrote:
> lgtm

Note: deriving from BaseChromiumApplication has the effect that
some chromium specific code is initialized that is not normally
initialized in apps.

[timvolodine, 2015-10-16 15:12:10]

The CQ bit was checked by timvolodine@chromium.org

[commit-bot: I haz the power, 2015-10-16 15:12:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1410023002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1410023002/1

[commit-bot: I haz the power, 2015-10-16 15:18:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-16 15:19:34]

Patchset 1 (id:??) landed as
https://crrev.com/5f4a677bdba5250ff3ed3fc829975cbe489d3d24
Cr-Commit-Position: refs/heads/master@{#354514}