Add key modifier on minimize/restore button click to minimize/restore all Panels for Mac.

chrome/browser/ui/panels/panel_strip.h

Index: chrome/browser/ui/panels/panel_strip.h
diff --git a/chrome/browser/ui/panels/panel_strip.h b/chrome/browser/ui/panels/panel_strip.h
index 21a8ffb2a6cef8ca2a08a1af9b9253547a08351e..e263a6bd11eb2943fde196f2e6e1d1a5a4d76140 100644
--- a/chrome/browser/ui/panels/panel_strip.h
+++ b/chrome/browser/ui/panels/panel_strip.h
@@ -90,10 +90,14 @@ class PanelStrip {
   // Updates the display to show |panel| as active.
   virtual void ActivatePanel(Panel* panel) = 0;
 
-  // Updates the display to show |panel| as  minimized/restored.
+  // Updates the display to show |panel| as minimized/restored.
   virtual void MinimizePanel(Panel* panel) = 0;
   virtual void RestorePanel(Panel* panel) = 0;
 
+  // Updates the display to show all panels in the strip as minimized/restored.
+  virtual void MinimizeAll() = 0;
+  virtual void RestoreAll() = 0;
+
   virtual bool CanMinimizePanel(const Panel* panel) const = 0;
   virtual bool IsPanelMinimized(const Panel* panel) const = 0;