Add GN arg to disable Alloy bootstrap (see #3681, see #3685)

Set enable_alloy_bootstrap=false to build with Alloy bootstrap code
removed. Extension API is documented as deprecated in comments but
not compiled out with this arg.

libcef/browser/alloy/browser_platform_delegate_alloy.cc

@@ -7,37 +7,55 @@
 #include <memory>
 
 #include "libcef/browser/alloy/alloy_browser_host_impl.h"
-#include "libcef/browser/alloy/dialogs/alloy_javascript_dialog_manager_delegate.h"
-#include "libcef/browser/extensions/browser_extensions_util.h"
 #include "libcef/browser/extensions/extension_background_host.h"
 #include "libcef/browser/extensions/extension_system.h"
 #include "libcef/browser/extensions/extension_view_host.h"
 #include "libcef/browser/extensions/extension_web_contents_observer.h"
 #include "libcef/common/extensions/extensions_util.h"
 #include "libcef/common/net/url_util.h"
-#include "libcef/features/runtime_checks.h"
 
 #include "base/logging.h"
-#include "chrome/browser/printing/printing_init.h"
+#include "cef/libcef/features/features.h"
 #include "chrome/browser/task_manager/web_contents_tags.h"
-#include "chrome/browser/ui/prefs/prefs_tab_helper.h"
 #include "chrome/browser/ui/tab_helpers.h"
 #include "components/find_in_page/find_tab_helper.h"
 #include "components/find_in_page/find_types.h"
-#include "components/javascript_dialogs/tab_modal_dialog_manager.h"
 #include "components/performance_manager/embedder/performance_manager_registry.h"
-#include "components/permissions/permission_request_manager.h"
-#include "components/zoom/zoom_controller.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/public/browser/render_view_host.h"
 #include "extensions/browser/process_manager.h"
 #include "pdf/pdf_features.h"
 #include "third_party/blink/public/mojom/frame/find_in_page.mojom.h"
 
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
+#include "libcef/browser/alloy/dialogs/alloy_javascript_dialog_manager_delegate.h"
+#include "libcef/features/runtime_checks.h"
+
+#include "chrome/browser/printing/printing_init.h"
+#include "chrome/browser/ui/prefs/prefs_tab_helper.h"
+#include "components/javascript_dialogs/tab_modal_dialog_manager.h"
+#include "components/permissions/permission_request_manager.h"
+#include "components/zoom/zoom_controller.h"
+#include "extensions/browser/extension_registry.h"
+#endif  // BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
+
 namespace {
 
 const char kAttachedHelpersUserDataKey[] = "CefAttachedHelpers";
 
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
+const extensions::Extension* GetExtensionForUrl(
+    content::BrowserContext* browser_context,
+    const GURL& url) {
+  auto* registry = extensions::ExtensionRegistry::Get(browser_context);
+  if (!registry) {
+    return nullptr;
+  }
+  std::string extension_id = url.host();
+  return registry->enabled_extensions().GetByID(extension_id);
+}
+#endif  // BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
+
 }  // namespace
 
 CefBrowserPlatformDelegateAlloy::CefBrowserPlatformDelegateAlloy()
@@ -58,13 +76,13 @@ content::WebContents* CefBrowserPlatformDelegateAlloy::CreateWebContents(
   CHECK(browser_context);
 
   scoped_refptr<content::SiteInstance> site_instance;
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
   if (extensions::ExtensionsEnabled() && !create_params.url.empty()) {
     GURL gurl = url_util::MakeGURL(create_params.url, /*fixup=*/true);
     if (!create_params.extension) {
       // We might be loading an extension app view where the extension URL is
       // provided by the client.
-      create_params.extension =
-          extensions::GetExtensionForUrl(browser_context, gurl);
+      create_params.extension = GetExtensionForUrl(browser_context, gurl);
     }
     if (create_params.extension) {
       if (create_params.extension_host_type ==
@@ -85,6 +103,7 @@ content::WebContents* CefBrowserPlatformDelegateAlloy::CreateWebContents(
       DCHECK(site_instance);
     }
   }
+#endif  // BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
 
   content::WebContents::CreateParams wc_create_params(browser_context,
                                                       site_instance);
@@ -138,13 +157,16 @@ void CefBrowserPlatformDelegateAlloy::AddNewContents(
     return;
   }
 
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
   if (extension_host_) {
     extension_host_->AddNewContents(source, std::move(new_contents), target_url,
                                     disposition, window_features, user_gesture,
                                     was_blocked);
   }
+#endif
 }
 
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
 bool CefBrowserPlatformDelegateAlloy::
     ShouldAllowRendererInitiatedCrossProcessNavigation(
         bool is_main_frame_navigation) {
@@ -154,6 +176,7 @@ bool CefBrowserPlatformDelegateAlloy::
   }
   return true;
 }
+#endif
 
 void CefBrowserPlatformDelegateAlloy::RenderViewReady() {
   ConfigureAutoResize();
@@ -179,6 +202,7 @@ void CefBrowserPlatformDelegateAlloy::BrowserCreated(
       std::make_unique<AlloyWebContentsDialogHelper>(web_contents_, this);
 }
 
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
 void CefBrowserPlatformDelegateAlloy::CreateExtensionHost(
     const extensions::Extension* extension,
     const GURL& url,
@@ -219,11 +243,14 @@ extensions::ExtensionHost* CefBrowserPlatformDelegateAlloy::GetExtensionHost()
     const {
   return extension_host_;
 }
+#endif  // BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
 
 void CefBrowserPlatformDelegateAlloy::BrowserDestroyed(
     CefBrowserHostBase* browser) {
   if (primary_) {
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
     DestroyExtensionHost();
+#endif
     owned_web_contents_.reset();
   }
 
@@ -265,6 +292,7 @@ void CefBrowserPlatformDelegateAlloy::NotifyMoveOrResizeStarted() {
 }
 #endif
 
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
 bool CefBrowserPlatformDelegateAlloy::PreHandleGestureEvent(
     content::WebContents* source,
     const blink::WebGestureEvent& event) {
@@ -281,6 +309,7 @@ bool CefBrowserPlatformDelegateAlloy::IsNeverComposited(
   }
   return false;
 }
+#endif  // BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
 
 void CefBrowserPlatformDelegateAlloy::SetAutoResizeEnabled(
     bool enabled,
@@ -377,6 +406,7 @@ void CefBrowserPlatformDelegateAlloy::SetOwnedWebContents(
   owned_web_contents_.reset(owned_contents);
 }
 
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
 void CefBrowserPlatformDelegateAlloy::DestroyExtensionHost() {
   if (!extension_host_) {
     return;
@@ -402,6 +432,7 @@ void CefBrowserPlatformDelegateAlloy::OnExtensionHostDeleted() {
   DCHECK(extension_host_);
   extension_host_ = nullptr;
 }
+#endif  // BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
 
 void CefBrowserPlatformDelegateAlloy::AttachHelpers(
     content::WebContents* web_contents) {
@@ -416,6 +447,7 @@ void CefBrowserPlatformDelegateAlloy::AttachHelpers(
   web_contents->SetUserData(&kAttachedHelpersUserDataKey,
                             std::make_unique<base::SupportsUserData::Data>());
 
+#if BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
   // Create all the helpers.
   if (cef::IsAlloyRuntimeEnabled()) {
     find_in_page::FindTabHelper::CreateForWebContents(web_contents);
@@ -427,7 +459,9 @@ void CefBrowserPlatformDelegateAlloy::AttachHelpers(
     javascript_dialogs::TabModalDialogManager::CreateForWebContents(
         web_contents, CreateAlloyJavaScriptTabModalDialogManagerDelegateDesktop(
                           web_contents));
-  } else {
+  } else
+#endif  // BUILDFLAG(ENABLE_ALLOY_BOOTSTRAP)
+  {
     if (IsWindowless()) {
       // Logic from ChromeContentBrowserClientCef::GetWebContentsViewDelegate
       // which is not called for windowless browsers. Needs to be done before