ash: Remove ash::Shelf in favor of ash::WmShelf

chrome/browser/chromeos/first_run/steps/tray_step.cc

Index: chrome/browser/chromeos/first_run/steps/tray_step.cc
diff --git a/chrome/browser/chromeos/first_run/steps/tray_step.cc b/chrome/browser/chromeos/first_run/steps/tray_step.cc
index 4e4192c7e05a5dfa03e1842566333420307cb9c1..e232d32d96b632eae3f662a37c911adeb4b7a84b 100644
--- a/chrome/browser/chromeos/first_run/steps/tray_step.cc
+++ b/chrome/browser/chromeos/first_run/steps/tray_step.cc
@@ -4,8 +4,8 @@
 
 #include "chrome/browser/chromeos/first_run/steps/tray_step.h"
 
-#include "ash/common/shelf/shelf.h"
 #include "ash/common/shelf/wm_shelf.h"
+#include "ash/common/wm_shell.h"
 #include "ash/first_run/first_run_helper.h"
 #include "base/i18n/rtl.h"
 #include "chrome/browser/chromeos/first_run/step_names.h"
@@ -29,7 +29,8 @@ void TrayStep::DoShow() {
   FirstRunActor::StepPosition position;
   position.SetTop(bounds.y());
   ash::ShelfAlignment alignment =
-      ash::Shelf::ForPrimaryDisplay()->wm_shelf()->alignment();
+      ash::WmShelf::ForWindow(ash::WmShell::Get()->GetPrimaryRootWindow())

[msw, 2016/08/30 22:02:07]

aside: maybe we should do this elsewhere instead of
ash::WmShell::Get()->GetPrimaryRootWindow()->GetRootWindowController()->GetShelf();
or maybe we *should* add WmShelf::GetPrimaryShelf despite my earlier hesitation.

[James Cook, 2016/08/30 23:00:57]

I cleaned up the other ones to call WmShelf::ForWindow(). I don't want to add
WmShelf::GetPrimaryShelf() -- people should have to work at least a little bit
harder before they do something evil. :-)

+          ->alignment();
   if ((!base::i18n::IsRTL() && alignment != ash::SHELF_ALIGNMENT_LEFT) ||
       alignment == ash::SHELF_ALIGNMENT_RIGHT)
     position.SetRight(GetOverlaySize().width() - bounds.x());