chrome: Support customization of context menus (see issue #2969)

libcef/browser/chrome/chrome_context_menu_handler.cc

@@ -0,0 +1,207 @@
+// Copyright (c) 2021 The Chromium Embedded Framework Authors. All rights
+// reserved. Use of this source code is governed by a BSD-style license that can
+// be found in the LICENSE file.
+
+#include "libcef/browser/chrome/chrome_context_menu_handler.h"
+
+#include "libcef/browser/browser_host_base.h"
+#include "libcef/browser/context_menu_params_impl.h"
+#include "libcef/browser/simple_menu_model_impl.h"
+
+#include "chrome/browser/renderer_context_menu/render_view_context_menu.h"
+
+namespace context_menu {
+
+namespace {
+
+// Lifespan is controlled by RenderViewContextMenu.
+class CefContextMenuObserver : public RenderViewContextMenuObserver,
+                               public CefSimpleMenuModelImpl::StateDelegate {
+ public:
+  CefContextMenuObserver(RenderViewContextMenu* context_menu,
+                         CefRefPtr<CefBrowserHostBase> browser,
+                         CefRefPtr<CefContextMenuHandler> handler)
+      : context_menu_(context_menu), browser_(browser), handler_(handler) {}
+
+  // RenderViewContextMenuObserver methods:
+
+  void InitMenu(const content::ContextMenuParams& params) override {
+    params_ = new CefContextMenuParamsImpl(
+        const_cast<content::ContextMenuParams*>(&context_menu_->params()));
+    model_ = new CefSimpleMenuModelImpl(
+        const_cast<ui::SimpleMenuModel*>(&context_menu_->menu_model()),
+        context_menu_, this, /*is_owned=*/false, /*is_popup=*/false);
+
+    handler_->OnBeforeContextMenu(browser_, GetFrame(), params_, model_);
+  }
+
+  bool IsCommandIdSupported(int command_id) override {
+    // Always claim support for the reserved user ID range.
+    if (command_id >= MENU_ID_USER_FIRST && command_id <= MENU_ID_USER_LAST)
+      return true;
+
+    // Also claim support in specific cases where an ItemInfo exists.
+    return GetItemInfo(command_id) != nullptr;
+  }
+
+  // Only called if IsCommandIdSupported() returns true.
+  bool IsCommandIdEnabled(int command_id) override {
+    // Always return true to use the SimpleMenuModel state.
+    return true;
+  }
+
+  // Only called if IsCommandIdSupported() returns true.
+  bool IsCommandIdChecked(int command_id) override {
+    auto* info = GetItemInfo(command_id);
+    return info ? info->checked : false;
+  }
+
+  // Only called if IsCommandIdSupported() returns true.
+  bool GetAccelerator(int command_id, ui::Accelerator* accel) override {
+    auto* info = GetItemInfo(command_id);
+    if (info && info->accel) {
+      *accel = *info->accel;
+      return true;
+    }
+    return false;
+  }
+
+  void CommandWillBeExecuted(int command_id) override {
+    if (handler_->OnContextMenuCommand(browser_, GetFrame(), params_,
+                                       command_id, EVENTFLAG_NONE)) {
+      // Create an ItemInfo so that we get the ExecuteCommand() callback
+      // instead of the default handler.
+      GetOrCreateItemInfo(command_id);
+    }
+  }
+
+  // Only called if IsCommandIdSupported() returns true.
+  void ExecuteCommand(int command_id) override {
+    auto* info = GetItemInfo(command_id);
+    if (info) {
+      // In case it was added in CommandWillBeExecuted().
+      MaybeDeleteItemInfo(command_id, info);
+    }
+  }
+
+  void OnMenuClosed() override {
+    handler_->OnContextMenuDismissed(browser_, GetFrame());
+    model_->Detach();
+
+    // Clear stored state because this object won't be deleted until a new
+    // context menu is created or the associated browser is destroyed.
+    browser_ = nullptr;
+    handler_ = nullptr;
+    params_ = nullptr;
+    model_ = nullptr;
+    iteminfomap_.clear();
+  }
+
+  // CefSimpleMenuModelImpl::StateDelegate methods:
+
+  void SetChecked(int command_id, bool checked) override {
+    // No-op if already at the default state.
+    if (!checked && !GetItemInfo(command_id))
+      return;
+
+    auto* info = GetOrCreateItemInfo(command_id);
+    info->checked = checked;
+    if (!checked)
+      MaybeDeleteItemInfo(command_id, info);
+  }
+
+  void SetAccelerator(int command_id,
+                      base::Optional<ui::Accelerator> accel) override {
+    // No-op if already at the default state.
+    if (!accel && !GetItemInfo(command_id))
+      return;
+
+    auto* info = GetOrCreateItemInfo(command_id);
+    info->accel = accel;
+    if (!accel)
+      MaybeDeleteItemInfo(command_id, info);
+  }
+
+ private:
+  struct ItemInfo {
+    ItemInfo() {}
+
+    bool checked = false;
+    base::Optional<ui::Accelerator> accel;
+  };
+
+  ItemInfo* GetItemInfo(int command_id) {
+    auto it = iteminfomap_.find(command_id);
+    if (it != iteminfomap_.end()) {
+      return &it->second;
+    }
+    return nullptr;
+  }
+
+  ItemInfo* GetOrCreateItemInfo(int command_id) {
+    if (auto info = GetItemInfo(command_id))
+      return info;
+
+    auto result = iteminfomap_.insert(std::make_pair(command_id, ItemInfo()));
+    return &result.first->second;
+  }
+
+  void MaybeDeleteItemInfo(int command_id, ItemInfo* info) {
+    // Remove if all info has reverted to the default state.
+    if (!info->checked && !info->accel) {
+      auto it = iteminfomap_.find(command_id);
+      iteminfomap_.erase(it);
+    }
+  }
+
+  CefRefPtr<CefFrame> GetFrame() const {
+    CefRefPtr<CefFrame> frame;
+
+    // May return nullptr if the frame is destroyed while the menu is pending.
+    auto* rfh = context_menu_->GetRenderFrameHost();
+    if (rfh) {
+      frame = browser_->GetFrameForHost(rfh);
+    }
+    if (!frame) {
+      frame = browser_->GetMainFrame();
+    }
+    return frame;
+  }
+
+  RenderViewContextMenu* const context_menu_;
+  CefRefPtr<CefBrowserHostBase> browser_;
+  CefRefPtr<CefContextMenuHandler> handler_;
+  CefRefPtr<CefContextMenuParams> params_;
+  CefRefPtr<CefSimpleMenuModelImpl> model_;
+
+  // Map of command_id to ItemInfo.
+  using ItemInfoMap = std::map<int, ItemInfo>;
+  ItemInfoMap iteminfomap_;
+
+  DISALLOW_COPY_AND_ASSIGN(CefContextMenuObserver);
+};
+
+std::unique_ptr<RenderViewContextMenuObserver> MenuCreatedCallback(
+    RenderViewContextMenu* context_menu) {
+  auto browser = CefBrowserHostBase::GetBrowserForContents(
+      context_menu->source_web_contents());
+  if (browser) {
+    if (auto client = browser->GetClient()) {
+      if (auto handler = client->GetContextMenuHandler()) {
+        return std::make_unique<CefContextMenuObserver>(context_menu, browser,
+                                                        handler);
+      }
+    }
+  }
+
+  return nullptr;
+}
+
+}  // namespace
+
+void RegisterMenuCreatedCallback() {
+  RenderViewContextMenu::RegisterMenuCreatedCallback(
+      base::BindRepeating(&MenuCreatedCallback));
+}
+
+}  // namespace context_menu