Move the logic for creating a new window as part of a "normal" load to CreateWindow.cpp. Hopefully this will enable us to merge more of that code with the window.open case in the future. The new window case now re-enters FrameLoader via its public api, instead of calling into the new FrameLoader's private loadWithNavigationAction().

Also, remove the ResourceRequest parameter from loadWithNavigationAction(), since it's redundant with part of the NavigationAction parameter.

BUG=none

Review URL: https://codereview.chromium.org/58283002

git-svn-id: svn://svn.chromium.org/blink/trunk@161843 bbb929c8-8fbe-4397-9dbb-9b2b20218538