[Android] Adjust XWalkPermissionClient::allowImage's signature.

The parent method's signature changed in Chromium r170983.
[Android] Adjust XWalkRenderViewExt::DidCommitProvisionalLoad's signature.

The parent method's signature changed in r261764.
[Android] Adjust RuntimeResourceDispatcherHostDelegateAndroid::HandleExternalProtocol's signature.

The parent method's signature changed in r261014.
[Android] Rename XWalkRenderViewHostExt::RenderViewGone.

The method was renamed to RenderProcessGone upstream in r210727 more
than a year ago.
Merge pull request #2301 from rakuco/android-method-signatures

[Android] Fix the signature of several methods.