Reland Track the active ExtensionKeybindingRegistry and make it available to EventRewriter.

chrome/browser/extensions/extension_keybinding_registry.h

Index: chrome/browser/extensions/extension_keybinding_registry.h
diff --git a/chrome/browser/extensions/extension_keybinding_registry.h b/chrome/browser/extensions/extension_keybinding_registry.h
index 85ec8d80eea3a15162c4201cda0c3a9a371d76fa..86bb2c687ff6ce2303c29f3f68f444c0b084834e 100644
--- a/chrome/browser/extensions/extension_keybinding_registry.h
+++ b/chrome/browser/extensions/extension_keybinding_registry.h
@@ -66,6 +66,9 @@ class ExtensionKeybindingRegistry : public content::NotificationObserver,
   void ExecuteCommand(const std::string& extension_id,
                       const ui::Accelerator& accelerator);
 
+  // Check whether the specified |accelerator| has been registered.
+  bool IsAcceleratorRegistered(const ui::Accelerator& accelerator) const;
+
  protected:
   // Add extension keybinding for the events defined by the |extension|.
   // |command_name| is optional, but if not blank then only the command
@@ -99,9 +102,6 @@ class ExtensionKeybindingRegistry : public content::NotificationObserver,
   void CommandExecuted(const std::string& extension_id,
                        const std::string& command);
 
-  // Check whether the specified |accelerator| has been registered.
-  bool IsAcceleratorRegistered(const ui::Accelerator& accelerator) const;
-
   // Add event target (extension_id, command name) to the target list of
   // |accelerator|. Note that only media keys can have more than one event
   // target.