https://bugs.webkit.org/show_bug.cgi?id=97774

Reviewed by Kenneth Rohde Christiansen.

Implements the handler for willSetInputMethodState in WebKit2 in Qt.
This is needed to tell the input method instance in Qt to commit its
preedit content when the focus has moved to another node to prevent a
bug where the old preedit string was kept as the preedit string and
the editor moved focus back to the old node when continuing to enter
text via the input method.

This behavior is analog to the behavior of the QtQuick text input
elements.

* UIProcess/API/qt/raw/qrawwebview.cpp:
(QRawWebViewPrivate::handleWillSetInputMethodState):
* UIProcess/API/qt/raw/qrawwebview_p_p.h:
(QRawWebViewPrivate):
* UIProcess/PageClient.h:
(PageClient):
* UIProcess/WebPageProxy.h:
(WebPageProxy):
* UIProcess/WebPageProxy.messages.in:
* UIProcess/qt/QtPageClient.cpp:
(WebKit::QtPageClient::handleWillSetInputMethodState):
(WebKit):
* UIProcess/qt/QtPageClient.h:
(QtPageClient):
* UIProcess/qt/QtWebPageEventHandler.cpp:
(WebKit::QtWebPageEventHandler::handleWillSetInputMethodState):
(WebKit):
* UIProcess/qt/QtWebPageEventHandler.h:
(QtWebPageEventHandler):
* UIProcess/qt/WebPageProxyQt.cpp:
(WebKit::WebPageProxy::willSetInputMethodState):
(WebKit):
* WebProcess/WebCoreSupport/WebEditorClient.cpp:
(WebKit::WebEditorClient::willSetInputMethodState):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@136126 268f45cc-cd09-0410-ab3c-d52691b4dbfc