add willHandleNavigationPolicy
nwuseragent attr of iframe

Fix rogerwang/node-webkit#1479

Conflicts:
	Source/bindings/bindings.gypi
	Source/core/html/HTMLIFrameElement.cpp
	Source/core/html/HTMLIFrameElement.idl
	Source/core/loader/FrameLoader.h
add missing file in af1fccb1cb
inherit user agent override from opener frame

this will cover window.open() case from an iframe
with 'nwuseragent' attribute
refactor willHandleNavigationPolicy

Use FrameLoadRequest rather than NavigationAction

Conflicts:
	Source/core/loader/FrameLoader.h
	Source/core/loader/FrameLoaderClient.h
	Source/web/FrameLoaderClientImpl.cpp
	Source/web/FrameLoaderClientImpl.h
call 'new-win-policy' handler on window.open

Conflicts:
	Source/core/page/CreateWindow.cpp
inherit parent iframe's nwuseragent attribute
fix crash on setting nwUserAgent attribute
refactor willHandleNavigationPolicy

Conflicts:
	Source/core/loader/FrameLoaderClient.h
	Source/web/FrameLoaderClientImpl.cpp
	Source/web/FrameLoaderClientImpl.h
use 'new-win-policy' for middle and ctrl click

Fix rogerwang/node-webkit#1547
backport fix