[Chromium] Add WebKit API for Pointer Lock

[Chromium] Add WebKit API for Pointer Lock
https://bugs.webkit.org/show_bug.cgi?id=76410

Reviewed by Darin Fisher.

Breaking up https://bugs.webkit.org/show_bug.cgi?id=75762
into a series of patches, this stubs out the API.

* public/WebWidget.h:
(WebKit::WebWidget::didCompletePointerLock):
(WebKit::WebWidget::didNotCompletePointerLock):
(WebKit::WebWidget::didLosePointerLock):
* public/WebWidgetClient.h:
(WebKit::WebWidgetClient::requestPointerLock):
(WebKit::WebWidgetClient::requestPointerUnlock):
(WebKit::WebWidgetClient::isPointerLocked):
* src/ChromeClientImpl.cpp:
(WebKit::ChromeClientImpl::requestPointerLock):
(WebKit::ChromeClientImpl::requestPointerUnlock):
(WebKit::ChromeClientImpl::isPointerLocked):
* src/ChromeClientImpl.h:
* src/WebViewImpl.cpp:
(WebKit::WebViewImpl::handleInputEvent):
(WebKit::WebViewImpl::didCompletePointerLock):
(WebKit::WebViewImpl::didNotCompletePointerLock):
(WebKit::WebViewImpl::didLosePointerLock):
(WebKit::WebViewImpl::requestPointerLock):
(WebKit::WebViewImpl::requestPointerUnlock):
(WebKit::WebViewImpl::isPointerLocked):
(WebKit::WebViewImpl::pointerLockMouseEvent):
* src/WebViewImpl.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105720 268f45cc-cd09-0410-ab3c-d52691b4dbfc