[MacViews] Implement AlwaysOnTop and VisibleOnAllWorkspaces.

ui/views/widget/native_widget_mac.mm

Index: ui/views/widget/native_widget_mac.mm
diff --git a/ui/views/widget/native_widget_mac.mm b/ui/views/widget/native_widget_mac.mm
index 10a1c9f7475a336beebc5d09e4fb5849a64a3520..940f17e92a492863ffbde064aedbb5939304a0b1 100644
--- a/ui/views/widget/native_widget_mac.mm
+++ b/ui/views/widget/native_widget_mac.mm
@@ -12,6 +12,7 @@
 #import "ui/base/cocoa/window_size_constants.h"
 #include "ui/gfx/font_list.h"
 #import "ui/gfx/mac/coordinate_conversion.h"
+#import "ui/gfx/mac/nswindow_frame_controls.h"
 #include "ui/native_theme/native_theme.h"
 #import "ui/views/cocoa/bridged_content_view.h"
 #import "ui/views/cocoa/bridged_native_widget.h"
@@ -83,6 +84,8 @@ void NativeWidgetMac::InitNativeWidget(const Widget::InitParams& params) {
   [window setReleasedWhenClosed:NO];  // Owned by scoped_nsobject.
   bridge_->Init(window, params);
 
+  SetAlwaysOnTop(params.keep_on_top);

[tapted, 2015/05/12 04:05:35]

I think... only call this when params.keep_on_top is true. But comment. i.e.

// Only set the always on top property during Init if it is true, since setting
// it can affect how the window is treated by Exposé.


Other options could be
 - only change collection behavior in SetAlwaysOnTop if it is being set `true`
  ( - but then should we try to restore when going to false?)
 - only change collection behavior in SetAlwaysOnTop if (collectionBehavior & (
NSWindowCollectionBehaviorManaged | NSWindowCollectionBehaviorTransient |
NSWindowCollectionBehaviorStationary)) is zero
  ( - i.e. nothing has tried to set it already, but then... what if something
later wants to set it?)


So I think if a window never opt in to always-on-top, we should just leave the
collection behavior alone.

[jackhou1, 2015/05/12 05:44:19]

Done.

+
   delegate_->OnNativeWidgetCreated(true);
 
   bridge_->SetFocusManager(GetWidget()->GetFocusManager());
@@ -377,16 +380,15 @@ bool NativeWidgetMac::IsActive() const {
 }
 
 void NativeWidgetMac::SetAlwaysOnTop(bool always_on_top) {
-  NOTIMPLEMENTED();
+  gfx::SetNSWindowAlwaysOnTop(GetNativeWindow(), always_on_top);
 }
 
 bool NativeWidgetMac::IsAlwaysOnTop() const {
-  NOTIMPLEMENTED();
-  return false;
+  return gfx::IsNSWindowAlwaysOnTop(GetNativeWindow());
 }
 
 void NativeWidgetMac::SetVisibleOnAllWorkspaces(bool always_visible) {
-  NOTIMPLEMENTED();
+  gfx::SetNSWindowVisibleOnAllWorkspaces(GetNativeWindow(), always_visible);
 }
 
 void NativeWidgetMac::Maximize() {