Add extension API to change window show state using chrome.windows.update().

chrome/browser/ui/gtk/browser_window_gtk.cc

Index: chrome/browser/ui/gtk/browser_window_gtk.cc
diff --git a/chrome/browser/ui/gtk/browser_window_gtk.cc b/chrome/browser/ui/gtk/browser_window_gtk.cc
index 774bd6ae9ebc67ae7acc645cf2d8529112254ee9..de718b94f331221ff34869dc276015f42b040055 100644
--- a/chrome/browser/ui/gtk/browser_window_gtk.cc
+++ b/chrome/browser/ui/gtk/browser_window_gtk.cc
@@ -845,6 +845,21 @@ bool BrowserWindowGtk::IsMinimized() const {
   return (state_ & GDK_WINDOW_STATE_ICONIFIED);
 }
 
+void BrowserWindowGtk::Maximize() {
+  gtk_window_maximize(window_);
+}
+
+void BrowserWindowGtk::Minimize() {
+  gtk_window_iconify(window_);
+}
+
+void BrowserWindowGtk::Restore() {
+  if (IsMaximized())
+    UnMaximize();
+  else if (IsMinimized())
+    gtk_window_deiconify(window_);
+}
+
 bool BrowserWindowGtk::ShouldDrawContentDropShadow() {
   return !IsMaximized() && UseCustomFrame();
 }