ScreenWin notifies DisplayObserver's when displays changed.

ScreenWin notifies DisplayObserver's when displays changed.

This is done by having ScreenWin listening to
WM_DISPLAYCHANGE via SingletonHwnd.

BUG=162827
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284794

[mlamouri (slow - plz ping), 2014-07-21 16:50:59]

oshima@chromium.org: Please review changes in 
* ui/gfx/

sky@chromium.org: Please review changes in 
* ui/views/

[sky, 2014-07-21 17:09:18]

https://codereview.chromium.org/401313003/diff/20001/ui/views/widget/desktop_...
File ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc (right):

https://codereview.chromium.org/401313003/diff/20001/ui/views/widget/desktop_...
ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc:733:
static_cast<gfx::ScreenWin*>(gfx::Screen::GetScreenFor(content_window_))
There may be multiple DesktopWindowTreeHostWin's on this display. I also don't
think DesktopWindowTreeHostWin should be the one responsible for communicating
this state. Can you use SingletonHwnd?

[mlamouri (slow - plz ping), 2014-07-21 17:15:09]

https://codereview.chromium.org/401313003/diff/20001/ui/views/widget/desktop_...
File ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc (right):

https://codereview.chromium.org/401313003/diff/20001/ui/views/widget/desktop_...
ui/views/widget/desktop_aura/desktop_window_tree_host_win.cc:733:
static_cast<gfx::ScreenWin*>(gfx::Screen::GetScreenFor(content_window_))
On 2014/07/21 17:09:18, sky wrote:
> There may be multiple DesktopWindowTreeHostWin's on this display.

I am using a coalescing timer in ScreenWin because of that.

> I also don't
> think DesktopWindowTreeHostWin should be the one responsible for communicating
> this state.

I agree.

> Can you use SingletonHwnd?

I wasn't aware of that. I will have a a look.

[mlamouri (slow - plz ping), 2014-07-22 10:33:38]

I have changed the implementation to use SingletonHwnd, PTAL.

[sky, 2014-07-22 17:41:18]

LGTM

https://codereview.chromium.org/401313003/diff/40001/ui/gfx/screen_win.cc
File ui/gfx/screen_win.cc (right):

https://codereview.chromium.org/401313003/diff/40001/ui/gfx/screen_win.cc#new...
ui/gfx/screen_win.cc:81: displays_ = BuildDisplays();
Move to member initializer list.

https://codereview.chromium.org/401313003/diff/40001/ui/gfx/screen_win.cc#new...
ui/gfx/screen_win.cc:198: std::vector<gfx::Display> ScreenWin::BuildDisplays()
const {
Since this doesn't need anything from ScreenWin move it to functions in the
anonymous namespace at the top of the file.

[oshima, 2014-07-22 17:45:02]

lgtm if sky's comments are addressed

[mlamouri (slow - plz ping), 2014-07-22 17:49:30]

Thanks for the quick review sky@. oshima@, PTAL.

[mlamouri (slow - plz ping), 2014-07-22 17:52:51]

https://codereview.chromium.org/401313003/diff/40001/ui/gfx/screen_win.cc
File ui/gfx/screen_win.cc (right):

https://codereview.chromium.org/401313003/diff/40001/ui/gfx/screen_win.cc#new...
ui/gfx/screen_win.cc:81: displays_ = BuildDisplays();
On 2014/07/22 17:41:18, sky wrote:
> Move to member initializer list.

Done.

https://codereview.chromium.org/401313003/diff/40001/ui/gfx/screen_win.cc#new...
ui/gfx/screen_win.cc:198: std::vector<gfx::Display> ScreenWin::BuildDisplays()
const {
On 2014/07/22 17:41:18, sky wrote:
> Since this doesn't need anything from ScreenWin move it to functions in the
> anonymous namespace at the top of the file.

Done.

[mlamouri (slow - plz ping), 2014-07-22 18:22:40]

The CQ bit was checked by mlamouri@chromium.org

[commit-bot: I haz the power, 2014-07-22 18:25:00]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/mlamouri@chromium.org/401313003/60001

[commit-bot: I haz the power, 2014-07-22 20:27:40]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_dbg_triggered_tests on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered...)
  linux_chromium_rel_swarming on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/linux_chromium_rel_sw...)
  mac_chromium_compile_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/mac_chromium_compile_...)
  win_chromium_rel on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/win_chromium_rel/buil...)

[commit-bot: I haz the power, 2014-07-22 23:15:35]

Change committed as 284794