<webview>: Update manifest doc

<webview>: Update manifest doc

This CL ensures that the manifest documentation refers to the webview documentation for the webview section.

BUG=362708
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=281754

[not at google - send to devlin, 2014-07-07 21:45:28]

lgtm

[Fady Samuel, 2014-07-07 21:46:13]

The CQ bit was checked by fsamuel@chromium.org

[commit-bot: I haz the power, 2014-07-07 21:47:56]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/fsamuel@chromium.org/376673003/1

[commit-bot: I haz the power, 2014-07-08 00:44:02]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_aosp on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_aosp/builds/9...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)

[commit-bot: I haz the power, 2014-07-08 01:24:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-07-08 01:24:49]

Try jobs failed on following builders:
  android_aosp on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_aosp/builds/9...)

[Fady Samuel, 2014-07-08 14:26:05]

The CQ bit was checked by fsamuel@chromium.org

[commit-bot: I haz the power, 2014-07-08 14:27:04]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/fsamuel@chromium.org/376673003/1

[commit-bot: I haz the power, 2014-07-08 15:10:53]

Change committed as 281754