Wires up immersive mode for chrome and mash

ash/common/frame/custom_frame_view_ash.h

Index: ash/common/frame/custom_frame_view_ash.h
diff --git a/ash/common/frame/custom_frame_view_ash.h b/ash/common/frame/custom_frame_view_ash.h
index 9409ba6fc46929bb4e85c21432aa10ce687dedbf..b2e50bedffb1845f9b4109c5762acb19816ec546 100644
--- a/ash/common/frame/custom_frame_view_ash.h
+++ b/ash/common/frame/custom_frame_view_ash.h
@@ -21,6 +21,7 @@ namespace ash {
 class FrameCaptionButtonContainerView;
 class HeaderView;
 class ImmersiveFullscreenController;
+class ImmersiveFullscreenControllerDelegate;
 
 // A NonClientFrameView used for packaged apps, dialogs and other non-browser
 // windows. It supports immersive fullscreen. When in immersive fullscreen, the
@@ -33,7 +34,16 @@ class ASH_EXPORT CustomFrameViewAsh : public views::NonClientFrameView {
   // Internal class name.
   static const char kViewClassName[];
 
-  explicit CustomFrameViewAsh(views::Widget* frame);
+  // |enable_immersive| controls whether ImmersiveFullscreenController is
+  // created for the CustomFrameViewAsh; if true and a WindowStateDelegate has
+  // not been set on the WindowState associated with |frame|, then an
+  // ImmersiveFullscreenController is created.
+  // If ImmersiveFullscreenControllerDelegate is not supplied, HeaderView is
+  // used as the ImmersiveFullscreenControllerDelegate.
+  explicit CustomFrameViewAsh(

[James Cook, 2016/08/24 17:00:32]

I think this would be clearer with two constructors:

CustomFrameViewAsh(frame)
CustomFrameViewAsh(frame, immersive_delegate, enable_immersive)

and have the first one use C++11 constructor delegation to call the second.

(Or change all the call sites, there are only 6 existing ones.)

[sky, 2016/08/24 19:23:28]

Can you outline why you feel having two constructors is clearer? It seems like
all you get with two constructors is the opportunity for different
documentation, but that's covered here. One benefit of a single constructor like
this is it's easy to see the defaults. Two constructors means you have to look
to the definition to see the behavior.

[James Cook, 2016/08/24 19:56:29]

This allows "new CustomFrameViewAsh(frame, delegate)" without the
enable_immersive parameter, which felt like a case you might not want. I don't
feel that strongly, though.

+      views::Widget* frame,
+      ImmersiveFullscreenControllerDelegate* immersive_delegate = nullptr,
+      bool enable_immersive = true);
   ~CustomFrameViewAsh() override;
 
   // Inits |immersive_fullscreen_controller| so that the controller reveals
@@ -94,6 +104,8 @@ class ASH_EXPORT CustomFrameViewAsh : public views::NonClientFrameView {
   // View which contains the title and window controls.
   HeaderView* header_view_;
 
+  ImmersiveFullscreenControllerDelegate* immersive_delegate_;
+
   DISALLOW_COPY_AND_ASSIGN(CustomFrameViewAsh);
 };