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..36f338aada10b1f680d1e00418453a4eeb83b58e 100644
--- a/ash/wm/workspace/frame_maximize_button.h
+++ b/ash/wm/workspace/frame_maximize_button.h
@@ -35,6 +35,9 @@ class ASH_EXPORT FrameMaximizeButton : public views::ImageButton {
   virtual void OnMouseReleased(const views::MouseEvent& event) OVERRIDE;
   virtual void OnMouseCaptureLost() OVERRIDE;
 
+  void set_is_left_right_enabled(bool e) { is_left_right_enabled_ = e; }
+  void set_is_maximize_enabled(bool e) { is_maximize_enabled_ = e; }
+
  protected:
   // ImageButton overrides:
   virtual SkBitmap GetImageToPaint() OVERRIDE;
@@ -84,6 +87,10 @@ 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_;