Track the active ExtensionKeybindingRegistry and make it available to EventRewriter.

chrome/browser/ui/views/toolbar/toolbar_view.cc

Index: chrome/browser/ui/views/toolbar/toolbar_view.cc
diff --git a/chrome/browser/ui/views/toolbar/toolbar_view.cc b/chrome/browser/ui/views/toolbar/toolbar_view.cc
index 573795fccd7857eeda603eeecd07b73870235446..b006cb6b9fbfb36607b5624af15914e539fc9748 100644
--- a/chrome/browser/ui/views/toolbar/toolbar_view.cc
+++ b/chrome/browser/ui/views/toolbar/toolbar_view.cc
@@ -14,6 +14,7 @@
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/command_updater.h"
+#include "chrome/browser/extensions/extension_commands_global_registry.h"
 #include "chrome/browser/extensions/extension_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/themes/theme_service.h"
@@ -270,9 +271,21 @@ void ToolbarView::Init() {
 
 void ToolbarView::OnWidgetVisibilityChanged(views::Widget* widget,
                                             bool visible) {
-  // Safe to call multiple times; the bubble will only appear once.
-  if (visible)
+  extensions::ExtensionKeybindingRegistry* registry = NULL;
+
+  if (visible) {
+    // Safe to call multiple times; the bubble will only appear once.
     extension_message_bubble_factory_->MaybeShow(app_menu_);
+    registry = browser_actions_->extension_keybinding_registry();
+  }
+
+  extensions::ExtensionCommandsGlobalRegistry::Get(browser_->profile())
+      ->set_active_registry(registry);

[Devlin, 2014/09/12 00:10:33]

Not quite.  We should only set this to NULL if we *were* the active registry. 
Something like:

ExtensionCommandsGlobalRegistry* global_command_registry =
    ExtensionCommandsGlobalRegistry::Get(browser_->profile());
if (visible) {
  extension_message_bubble_factory_->MaybeShow(app_menu_);
  global_command_registry->set_active_registry(
      browser_actions_->extension_keybinding_registry());
} else if (global_command_registry->active_registry() ==
               browser_actions_->extension_keybinding_registry()) {
  global_command_registry->set_active_registry(NULL);
}

The point is to set the registry to NULL if and only if this *was* the active
registry to begin with (otherwise, the currently-active registry will still be
valid).

Same goes for OnWidgetDestroyed() code.

[David Tseng, 2014/09/12 01:26:58]

Yup; you're totally right. Done.

+}
+
+void ToolbarView::OnWidgetDestroyed(views::Widget* widget) {
+  extensions::ExtensionCommandsGlobalRegistry::Get(browser_->profile())
+      ->set_active_registry(NULL);
 }
 
 void ToolbarView::Update(WebContents* tab) {