Add key modifier to minimize/restore button click to minimize/restore-all panels for Windows.

chrome/browser/ui/panels/panel_browser_view.h

Index: chrome/browser/ui/panels/panel_browser_view.h
diff --git a/chrome/browser/ui/panels/panel_browser_view.h b/chrome/browser/ui/panels/panel_browser_view.h
index a8e20deb4b607d26815cd03c7773202ffb76457f..6762593bfc8460b0d76ab2367ee175b6b78bcbc3 100644
--- a/chrome/browser/ui/panels/panel_browser_view.h
+++ b/chrome/browser/ui/panels/panel_browser_view.h
@@ -38,11 +38,15 @@ class PanelBrowserView : public BrowserView,
   // Called from frame view when titlebar receives a mouse event.
   // Return true if the event is handled.
   // |mouse_location| is in screen coordinates.
-  bool OnTitlebarMousePressed(const gfx::Point& mouse_location);
-  bool OnTitlebarMouseDragged(const gfx::Point& mouse_location);
-  bool OnTitlebarMouseReleased();
+  bool OnTitlebarMousePressed(const views::MouseEvent& event);
+  bool OnTitlebarMouseDragged(const views::MouseEvent& event);
+  bool OnTitlebarMouseReleased(const views::MouseEvent& event);
   bool OnTitlebarMouseCaptureLost();
 
+  // Called from frame view when minimize/restore button is pressed.
+  void MinimizeButtonPressed(const views::Event& event);
+  void RestoreButtonPressed(const views::Event& event);
+
  private:
   friend class NativePanelTestingWin;
   friend class PanelBrowserViewTest;