REGRESSION(r165841): Messages sent before the child process is launched are never sent after r165841
https://bugs.webkit.org/show_bug.cgi?id=131675

Reviewed by Anders Carlsson.

Since r165841 the connection is opened after the pending messages
are sent, because connectionWillOpen might send messages that we
want to happen after the ones already pending. The problem is that
Connection::canSendOutgoingMessages() returns false when
connection hasn't been opened. We should ensure no messages are
sent by connectionWillOpen.

* Shared/ChildProcessProxy.cpp:
(WebKit::ChildProcessProxy::didFinishLaunching): Open the
connection before sending pending messages.
* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::connectionWillOpen): Do not call
VisitedLinkProvider::addProcess() here because it tries to send a
message to the web process, but the connection hasn't be opened yet.
(WebKit::WebPageProxy::processDidFinishLaunching): Call
VisitedLinkProvider::addProcess() here instead.
* UIProcess/WebPageProxy.h:
* UIProcess/WebProcessProxy.cpp:
(WebKit::WebProcessProxy::didFinishLaunching): Call
WebPageProxy::processDidFinishLaunching() for every web page.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@169306 268f45cc-cd09-0410-ab3c-d52691b4dbfc