Implement initial chrome.browserAction.openPopup API.

chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc

Index: chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc
diff --git a/chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc b/chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc
index 34f300ac07e04720260efa3d538186ec84698fb7..9ea37bd7daf0f56b7b097df29bf38b22edb3675d 100644
--- a/chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc
+++ b/chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc
@@ -24,6 +24,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/gtk/browser_window_gtk.h"
 #include "chrome/browser/ui/gtk/custom_button.h"
 #include "chrome/browser/ui/gtk/extensions/extension_popup_gtk.h"
@@ -768,6 +769,22 @@ void BrowserActionsToolbarGtk::BrowserActionMoved(const Extension* extension,
   gtk_box_reorder_child(GTK_BOX(button_hbox_.get()), button_widget, index);
 }
 
+void BrowserActionsToolbarGtk::BrowserActionShowPopup(
+    const Extension* extension) {
+  // Do not override other popups and only show in active window.
+  if (ExtensionPopupGtk::get_current_extension_popup() != NULL ||
+      BrowserList::GetInstance(chrome::GetActiveDesktop())->GetLastActive() !=
+          browser()) {
+    return;
+  }
+
+  GURL popup_url = model_->GetPopupUrl(extension, browser());
+  if (!popup_url.is_empty()) {
+    ExtensionPopupGtk::Show(popup_url, browser(), chevron() /*button->widget()*/,
+                            ExtensionPopupGtk::SHOW);
+  }
+}
+
 void BrowserActionsToolbarGtk::ModelLoaded() {
   SetContainerWidth();
 }