Added support for displaying the select folder picker in Chrome ASH on Windows 8.

Added support for displaying the select folder picker in Chrome ASH on Windows 8.

The current behavior is that the select folder picker displays in desktop mode even when
when performed in ASH.

Fixes are as below:-
1. In the Chrome browser added plumbing in the SelectFileDialogImpl class to forward this
   operation of to the metro viewer process via the newly added function HandedSelectFolder
   which lives in the aura namespace in the remote_window_host_win.cc file.

2. In the metro viewer code added a new class FolderPickerSession which provides the functionality
   for displaying the metro select folder picker and returning the results from the same.

3. The following IPC messages provide the necessary functionality to funnel the request
   and the result between the browser and the metro viewer process.
   MetroViewerHostMsg_DisplaySelectFolder
   MetroViewerHostMsg_SelectFolderDone

I also added code to save away the metro root window in the RemoteRootWindowHostWin class
when we receive the MetroViewerHostMsg_SetTargetSurface IPC from the viewer process. We 
return this window in the RemoteRootWindowHostWin::GetAcceleratedWidget function. This
change although not needed for this CL seems correct. 

BUG=230087
R=cpu,sky

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=195224

[cpu_(ooo_6.6-7.5), 2013-04-16 22:24:14]

can we remove the metro_window_ thing from this CL?

Lets make a different CL with it and discuss that there.

[cpu_(ooo_6.6-7.5), 2013-04-16 22:25:20]

When the user switches away from metro, we need to cancel any folder picking, is
that happening today?

[ananta, 2013-04-17 01:05:57]

On 2013/04/16 22:25:20, cpu wrote:
> When the user switches away from metro, we need to cancel any folder picking,
is
> that happening today?

I removed the metro_window_ changes from this CL. Regarding the cancelling of
the folder_picking when we switch away from Chrome, as per our discussion
leaving this behavior as is.

[cpu_(ooo_6.6-7.5), 2013-04-17 21:46:59]

lgtm

[ananta, 2013-04-17 22:05:32]

Adding Ben for ui OWNERS lgtm

[Ben Goodger (Google), 2013-04-18 18:20:53]

lgtm

[palmer, 2013-04-18 22:58:07]

https://codereview.chromium.org/14282002/diff/15001/ui/aura/remote_root_windo...
File ui/aura/remote_root_window_host_win.cc (right):

https://codereview.chromium.org/14282002/diff/15001/ui/aura/remote_root_windo...
ui/aura/remote_root_window_host_win.cc:170: // Can only have have one of these
operations in flight.
Only need one "have". :)

https://codereview.chromium.org/14282002/diff/15001/ui/metro_viewer/metro_vie...
File ui/metro_viewer/metro_viewer_messages.h (right):

https://codereview.chromium.org/14282002/diff/15001/ui/metro_viewer/metro_vie...
ui/metro_viewer/metro_viewer_messages.h:91: string16)       /* filepath*/
This, and the others, should really be base::FilePath. Can you please change
this one, and file a bug to convert the others too?

[ananta, 2013-04-19 00:23:24]

https://codereview.chromium.org/14282002/diff/15001/ui/aura/remote_root_windo...
File ui/aura/remote_root_window_host_win.cc (right):

https://codereview.chromium.org/14282002/diff/15001/ui/aura/remote_root_windo...
ui/aura/remote_root_window_host_win.cc:170: // Can only have have one of these
operations in flight.
On 2013/04/18 22:58:08, Chromium Palmer wrote:
> Only need one "have". :)

Done.

https://codereview.chromium.org/14282002/diff/15001/ui/metro_viewer/metro_vie...
File ui/metro_viewer/metro_viewer_messages.h (right):

https://codereview.chromium.org/14282002/diff/15001/ui/metro_viewer/metro_vie...
ui/metro_viewer/metro_viewer_messages.h:91: string16)       /* filepath*/
On 2013/04/18 22:58:08, Chromium Palmer wrote:
> This, and the others, should really be base::FilePath. Can you please change
> this one, and file a bug to convert the others too?
I changed all the IPCs to take in FilePaths.

[palmer, 2013-04-19 01:10:28]

IPC security LGTM. Thanks!

[ananta, 2013-04-19 17:44:26]

Committed patchset #4 manually as r195224 (presubmit successful).