Revert 245051 "Don't set the scroll styles (WS_VSCROLL and WS_HS..."

Seems to be causing lots of layout test failures on Win7

> Don't set the scroll styles (WS_VSCROLL and WS_HSCROLL) for WS_POPUP windows.
> 
> This causes issues with select boxes on Windows 7 where hovering at the end of the window returns the scroll WM_NCHITTEST
> codes. Works fine on Windows 8. In any case we don't want the scrolling styles set on windows other than the main Chrome window
> which is the only window which should be receive mousewheel messages.
> 
> I moved the scroll style setting code from the HWNDMessageHandler::OnCreate function to HWNDMessageHandler::Init function as that
> would prevent the initial WM_SIZE message from hiding the scrollbar. The other change is to hide the scrollbars and readd the
> scroll styles if we are sizing the window, when the sizing completes. Basically when we receive the WM_EXITSIZEMOVE message.
> For normal sizing operations we continue to do this in WM_SIZE as before.
> 
> From testing on my thinkpad with Win7, desktop with Win7 and Win8 this works well.
> 
> BUG=334454,334541
> R=sky@chromium.org, sky
> 
> Review URL: https://codereview.chromium.org/137403008

TBR=ananta@chromium.org

Review URL: https://codereview.chromium.org/137443018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245191 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245191