Implement "pinned" mode in ash.

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 9d15218621caed7de0e2b2a5fbb747e93603d93b..882850322bd77516bf516255297cc04f0484ae05 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -75,6 +75,7 @@
 #include "ash/wm/overlay_event_filter.h"
 #include "ash/wm/overview/scoped_overview_animation_settings_factory_aura.h"
 #include "ash/wm/overview/window_selector_controller.h"
+#include "ash/wm/pinned_controller.h"
 #include "ash/wm/power_button_controller.h"
 #include "ash/wm/resize_shadow_controller.h"
 #include "ash/wm/system_gesture_event_filter.h"
@@ -790,6 +791,10 @@ Shell::~Shell() {
   power_button_controller_.reset();
   lock_state_controller_.reset();
 
+  window_tree_host_manager_->RemoveObserver(pinned_controller_.get());
+  wm_shell_common_->RemoveShellObserver(pinned_controller_.get());
+  pinned_controller_.reset();
+
 #if defined(OS_CHROMEOS)
   resolution_notification_controller_.reset();
 #endif
@@ -1016,6 +1021,9 @@ void Shell::Init(const ShellInitParams& init_params) {
 #if defined(OS_CHROMEOS)
   sticky_keys_controller_.reset(new StickyKeysController);
 #endif
+  pinned_controller_.reset(new wm::PinnedController);

[oshima, 2016/06/17 10:26:54]

could you please reset explicitly?

[hidehiko, 2016/06/17 17:19:22]

It is already explicit?

[oshima, 2016/06/18 04:47:44]

Sorry I think I need more sleep.

+  wm_shell_common_->AddShellObserver(pinned_controller_.get());
+  window_tree_host_manager_->AddObserver(pinned_controller_.get());

[oshima, 2016/06/17 10:26:54]

Can you do this in PinnedController ctor , and remove in dtor?

[hidehiko, 2016/06/17 17:19:22]

Done.

 
   lock_state_controller_.reset(new LockStateController);
   power_button_controller_.reset(new PowerButtonController(