diff --git chrome/browser/renderer_context_menu/render_view_context_menu.cc chrome/browser/renderer_context_menu/render_view_context_menu.cc
index 15b3d1c767883..717ff131cadb5 100644
--- chrome/browser/renderer_context_menu/render_view_context_menu.cc
+++ chrome/browser/renderer_context_menu/render_view_context_menu.cc
@@ -319,6 +319,13 @@ base::OnceCallback<void(RenderViewContextMenu*)>* GetMenuShownCallback() {
   return callback.get();
 }
 
+
+RenderViewContextMenu::MenuCreatedCallback* GetMenuCreatedCallback() {
+  static base::NoDestructor<RenderViewContextMenu::MenuCreatedCallback>
+      callback;
+  return callback.get();
+}
+
 enum class UmaEnumIdLookupType {
   GeneralEnumId,
   ContextSpecificEnumId,
@@ -565,6 +572,10 @@ int FindUMAEnumValueForCommand(int id, UmaEnumIdLookupType type) {
   if (ContextMenuMatcher::IsExtensionsCustomCommandId(id))
     return 1;
 
+  // Match the MENU_ID_USER_FIRST to MENU_ID_USER_LAST range from cef_types.h.
+  if (id >= 26500 && id <= 28500)
+    return 1;
+
   id = CollapseCommandsForUMA(id);
   const auto& map = GetIdcToUmaMap(type);
   auto it = map.find(id);
@@ -785,6 +796,14 @@ RenderViewContextMenu::RenderViewContextMenu(
 #if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
   pdf_ocr_submenu_model_ = std::make_unique<ui::SimpleMenuModel>(this);
 #endif  // BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
+
+  auto* cb = GetMenuCreatedCallback();
+  if (!cb->is_null()) {
+    first_observer_ = cb->Run(this);
+    if (first_observer_) {
+      observers_.AddObserver(first_observer_.get());
+    }
+  }
 }
 
 RenderViewContextMenu::~RenderViewContextMenu() = default;
@@ -1202,6 +1221,12 @@ void RenderViewContextMenu::InitMenu() {
   // menu, meaning that each menu item added/removed in this function will cause
   // it to visibly jump on the screen (see b/173569669).
   AppendQuickAnswersItems();
+
+  if (first_observer_) {
+    // Do this last so that the observer can optionally modify previously
+    // created items.
+    first_observer_->InitMenu(params_);
+  }
 }
 
 Profile* RenderViewContextMenu::GetProfile() const {
@@ -3164,6 +3189,12 @@ void RenderViewContextMenu::RegisterExecutePluginActionCallbackForTesting(
   execute_plugin_action_callback_ = std::move(cb);
 }
 
+// static
+void RenderViewContextMenu::RegisterMenuCreatedCallback(
+    MenuCreatedCallback cb) {
+  *GetMenuCreatedCallback() = cb;
+}
+
 custom_handlers::ProtocolHandlerRegistry::ProtocolHandlerList
 RenderViewContextMenu::GetHandlersForLinkUrl() {
   custom_handlers::ProtocolHandlerRegistry::ProtocolHandlerList handlers =
diff --git chrome/browser/renderer_context_menu/render_view_context_menu.h chrome/browser/renderer_context_menu/render_view_context_menu.h
index b0505bb7375ee..85b9a58b4655f 100644
--- chrome/browser/renderer_context_menu/render_view_context_menu.h
+++ chrome/browser/renderer_context_menu/render_view_context_menu.h
@@ -142,6 +142,12 @@ class RenderViewContextMenu
   }
 #endif
 
+  // Registers a callback that will be called each time a context menu is
+  // created.
+  using MenuCreatedCallback = base::RepeatingCallback<
+      std::unique_ptr<RenderViewContextMenuObserver>(RenderViewContextMenu*)>;
+  static void RegisterMenuCreatedCallback(MenuCreatedCallback cb);
+
  protected:
   Profile* GetProfile() const;
 
@@ -394,6 +400,9 @@ class RenderViewContextMenu
   //   built.
   bool is_protocol_submenu_valid_ = false;
 
+  // An observer returned via MenuCreatedCallback that will be called first.
+  std::unique_ptr<RenderViewContextMenuObserver> first_observer_;
+
   // An observer that handles spelling suggestions, "Add to dictionary", and
   // "Use enhanced spell check" items.
   std::unique_ptr<SpellingMenuObserver> spelling_suggestions_menu_observer_;
diff --git chrome/browser/ui/views/renderer_context_menu/render_view_context_menu_views.cc chrome/browser/ui/views/renderer_context_menu/render_view_context_menu_views.cc
index b7522152d2c6d..5201ebe8268f1 100644
--- chrome/browser/ui/views/renderer_context_menu/render_view_context_menu_views.cc
+++ chrome/browser/ui/views/renderer_context_menu/render_view_context_menu_views.cc
@@ -149,6 +149,9 @@ void RenderViewContextMenuViews::RunMenuAt(views::Widget* parent,
 bool RenderViewContextMenuViews::GetAcceleratorForCommandId(
     int command_id,
     ui::Accelerator* accel) const {
+  if (RenderViewContextMenu::GetAcceleratorForCommandId(command_id, accel))
+    return true;
+
   // There are no formally defined accelerators we can query so we assume
   // that Ctrl+C, Ctrl+V, Ctrl+X, Ctrl-A, etc do what they normally do.
   switch (command_id) {
diff --git components/renderer_context_menu/render_view_context_menu_base.cc components/renderer_context_menu/render_view_context_menu_base.cc
index 965a283dea477..74c1ee8258485 100644
--- components/renderer_context_menu/render_view_context_menu_base.cc
+++ components/renderer_context_menu/render_view_context_menu_base.cc
@@ -382,6 +382,17 @@ bool RenderViewContextMenuBase::IsCommandIdChecked(int id) const {
   return false;
 }
 
+bool RenderViewContextMenuBase::GetAcceleratorForCommandId(
+    int id,
+    ui::Accelerator* accelerator) const {
+  for (auto& observer : observers_) {
+    if (observer.IsCommandIdSupported(id))
+      return observer.GetAccelerator(id, accelerator);
+  }
+
+  return false;
+}
+
 void RenderViewContextMenuBase::ExecuteCommand(int id, int event_flags) {
   command_executed_ = true;
   RecordUsedItem(id);
diff --git components/renderer_context_menu/render_view_context_menu_base.h components/renderer_context_menu/render_view_context_menu_base.h
index ee6e005771119..91b5867cd16bf 100644
--- components/renderer_context_menu/render_view_context_menu_base.h
+++ components/renderer_context_menu/render_view_context_menu_base.h
@@ -87,6 +87,9 @@ class RenderViewContextMenuBase : public ui::SimpleMenuModel::Delegate,
 
   const ui::SimpleMenuModel& menu_model() const { return menu_model_; }
   const content::ContextMenuParams& params() const { return params_; }
+  content::WebContents* source_web_contents() const {
+    return source_web_contents_;
+  }
 
   // Returns true if the specified command id is known and valid for
   // this menu. If the command is known |enabled| is set to indicate
@@ -95,6 +98,9 @@ class RenderViewContextMenuBase : public ui::SimpleMenuModel::Delegate,
 
   // SimpleMenuModel::Delegate implementation.
   bool IsCommandIdChecked(int command_id) const override;
+  bool GetAcceleratorForCommandId(
+      int command_id,
+      ui::Accelerator* accelerator) const override;
   void ExecuteCommand(int command_id, int event_flags) override;
   void OnMenuWillShow(ui::SimpleMenuModel* source) override;
   void MenuClosed(ui::SimpleMenuModel* source) override;
diff --git components/renderer_context_menu/render_view_context_menu_observer.cc components/renderer_context_menu/render_view_context_menu_observer.cc
index 9fdda1636003d..538bd05a41296 100644
--- components/renderer_context_menu/render_view_context_menu_observer.cc
+++ components/renderer_context_menu/render_view_context_menu_observer.cc
@@ -15,3 +15,8 @@ bool RenderViewContextMenuObserver::IsCommandIdChecked(int command_id) {
 bool RenderViewContextMenuObserver::IsCommandIdEnabled(int command_id) {
   return false;
 }
+
+bool RenderViewContextMenuObserver::GetAccelerator(int command_id,
+                                                   ui::Accelerator* accel) {
+  return false;
+}
diff --git components/renderer_context_menu/render_view_context_menu_observer.h components/renderer_context_menu/render_view_context_menu_observer.h
index 0527c57abd51c..70bebcbb50461 100644
--- components/renderer_context_menu/render_view_context_menu_observer.h
+++ components/renderer_context_menu/render_view_context_menu_observer.h
@@ -11,6 +11,10 @@ namespace content {
 struct ContextMenuParams;
 }
 
+namespace ui {
+class Accelerator;
+}
+
 // The interface used for implementing context-menu items. The following
 // instruction describe how to implement a context-menu item with this
 // interface.
@@ -100,6 +104,8 @@ class RenderViewContextMenuObserver {
   virtual bool IsCommandIdChecked(int command_id);
   virtual bool IsCommandIdEnabled(int command_id);
 
+  virtual bool GetAccelerator(int command_id, ui::Accelerator* accel);
+
   // Called when a user selects the specified context-menu item. This is
   // only called when the observer returns true for IsCommandIdSupported()
   // for that |command_id|.