Add flag to enable immersive fullscreen for v2 apps

apps/shell_window.h

Index: apps/shell_window.h
diff --git a/apps/shell_window.h b/apps/shell_window.h
index c236a1d7354f0c6c3f5935b41870a48c817b22a0..2f8ce91d093fe953953bfebb5d82be15a505f906 100644
--- a/apps/shell_window.h
+++ b/apps/shell_window.h
@@ -92,6 +92,30 @@ class ShellWindow : public content::NotificationObserver,
     FRAME_NONE,  // Frameless window.
   };
 
+  enum FullscreenType {
+    // Normal fullscreen. Primarily used by the app.window api. The window takes
+    // up the entire screen and the window header (title bar and window
+    // controls) is hidden.
+    FULLSCREEN_TYPE_WINDOW,
+
+    // Fullscreen entered by HTML requestFullscreen(). The HTML element on which
+    // requestFullscreen() was called takes up the entire screen and the widnow
+    // header is hidden.
+    FULLSCREEN_TYPE_TAB,
+
+    // Combination of "window" fullscreen and fullscreen entered by HTML
+    // requestFullscreen().
+    FULLSCREEN_TYPE_WINDOW_AND_TAB,
+
+    // Fullscreen entered by hitting <F4> on ChromeOS. The window header slides
+    // onscreen as an overlay when the mouse is hovered at the top of the
+    // screen.
+    FULLSCREEN_TYPE_IMMERSIVE,
+
+    // Not fullscreen.
+    FULLSCREEN_TYPE_NONE
+  };
+
   class SizeConstraints {
    public:
     // The value SizeConstraints uses to represent an unbounded width or height.
@@ -284,6 +308,11 @@ class ShellWindow : public content::NotificationObserver,
   void Minimize();
   void Restore();
 
+  // Transitions into immersive fullscreen if immersive fullscreen is supported
+  // and to "window" fullscreen otherwise. See FULLSCREEN_TYPE_IMMERSIVE for
+  // more details.
+  void ImmersiveFullscreen();
+
   // Set the minimum and maximum size that this window is allowed to be.
   void SetMinimumSize(const gfx::Size& min_size);
   void SetMaximumSize(const gfx::Size& max_size);
@@ -310,6 +339,11 @@ class ShellWindow : public content::NotificationObserver,
     return size_constraints_;
   }
 
+  // Get the fullscreen type.
+  FullscreenType fullscreen_type() const {
+    return fullscreen_type_;
+  }
+
  protected:
   virtual ~ShellWindow();
 
@@ -444,10 +478,8 @@ class ShellWindow : public content::NotificationObserver,
 
   base::WeakPtrFactory<ShellWindow> image_loader_ptr_factory_;
 
-  // Fullscreen entered by app.window api.
-  bool fullscreen_for_window_api_;
-  // Fullscreen entered by HTML requestFullscreen.
-  bool fullscreen_for_tab_;
+  // The fullscreen type.
+  FullscreenType fullscreen_type_;
 
   // Size constraints on the window.
   SizeConstraints size_constraints_;