Disable left/right/maximize for panels.

ash/wm/workspace/frame_maximize_button.h

Index: ash/wm/workspace/frame_maximize_button.h
diff --git a/ash/wm/workspace/frame_maximize_button.h b/ash/wm/workspace/frame_maximize_button.h
index 6a8bf8845e1397b718cc32c2381e5d11007ca307..5019489af30243067e5ff69f83f946d662dc2c9c 100644
--- a/ash/wm/workspace/frame_maximize_button.h
+++ b/ash/wm/workspace/frame_maximize_button.h
@@ -35,6 +35,11 @@ class ASH_EXPORT FrameMaximizeButton : public views::ImageButton {
   virtual void OnMouseReleased(const views::MouseEvent& event) OVERRIDE;
   virtual void OnMouseCaptureLost() OVERRIDE;
 
+  // Sets is_left_right_enabled_ and updates tooltip.
+  void SetIsLeftRightEnabled(bool e);
+
+  void set_is_maximize_enabled(bool e) { is_maximize_enabled_ = e; }
+
  protected:
   // ImageButton overrides:
   virtual SkBitmap GetImageToPaint() OVERRIDE;
@@ -61,6 +66,9 @@ class ASH_EXPORT FrameMaximizeButton : public views::ImageButton {
   // Updates |snap_type_| based on a mouse drag.
   void UpdateSnap(const gfx::Point& location);
 
+  // Returns true if maximizing is allowed.
+  bool AllowMaximize() const;
+
   // Returns the type of snap based on the specified location.
   SnapType SnapTypeForLocation(const gfx::Point& location) const;
 
@@ -84,6 +92,10 @@ class ASH_EXPORT FrameMaximizeButton : public views::ImageButton {
   // should show the snap locations.
   bool is_snap_enabled_;
 
+  // Selectively enable/disable button functionality.
+  bool is_left_right_enabled_;
+  bool is_maximize_enabled_;
+
   // Did the user drag far enough to trigger snapping?
   bool exceeded_drag_threshold_;