[BugFix][ElementTemplate] Notify DevTool typed page root

- Notify DevTool with the materialized typed page root when creating a typed page ElementTemplate, so the existing page-root path initializes element_root_.

- Keep InspectorTasmExecutor root handling limited to page nodes instead of deriving roots from arbitrary child insertion events.

- Add unit coverage that typed page ElementTemplate creation reports the materialized page root to the inspector observer.

TEST: tools/env.sh clang-format --dry-run --Werror lynx/core/runtime/lepus/bindings/renderer_functions.cc lynx/core/renderer/dom/fiber/fiber_element_unittest.cc lynx/devtool/lynx_devtool/agent/inspector_tasm_executor.cc lynx/devtool/lynx_devtool/agent/inspector_tasm_executor.h lynx/devtool/lynx_devtool/agent/inspector_tasm_executor_unittest.cc

TEST: git diff --check -- lynx/core/runtime/lepus/bindings/renderer_functions.cc lynx/core/renderer/dom/fiber/fiber_element_unittest.cc lynx/devtool/lynx_devtool/agent/inspector_tasm_executor.cc lynx/devtool/lynx_devtool/agent/inspector_tasm_executor.h lynx/devtool/lynx_devtool/agent/inspector_tasm_executor_unittest.cc

TEST: tools/env.sh python3 tools_shared/git_lynx.py check --checkers cpp-header-path --changed

TEST: tools/env.sh lynx/tools/rtf/rtf native-ut run --name lynx --target dom_unittest_exec

TEST: tools/env.sh lynx/tools/rtf/rtf native-ut run --name lynx --target devtool_agent_unittest_exec

AutoSubmit:True

Author: ShouruiSong

core/renderer/dom/fiber/fiber_element_unittest.cc

@@ -8,9 +8,12 @@
 #include "core/renderer/dom/fiber/fiber_element.h"
 
 #include <cmath>
+#include <functional>
+#include <map>
 #include <memory>
 #include <mutex>
 #include <tuple>
+#include <vector>
 
 #include "base/include/auto_reset.h"
 #include "core/animation/css_transition_manager.h"
@@ -103,6 +106,39 @@ bool LayoutBundleHasStyle(const std::unique_ptr<LayoutBundle>& layout_bundle,
   return false;
 }
 
+class RecordingInspectorElementObserver final
+    : public InspectorElementObserver {
+ public:
+  void OnDocumentUpdated() override {}
+  void OnElementNodeAdded(Element* ptr) override { added_nodes.push_back(ptr); }
+  void OnElementNodeRemoved(Element* ptr) override {}
+  void OnCharacterDataModified(Element* ptr) override {}
+  void OnElementDataModelSet(Element* ptr) override {}
+  void OnElementManagerWillDestroy() override {}
+  void OnCSSStyleSheetAdded(Element* ptr) override {}
+  void OnComponentUselessUpdate(const std::string& component_name,
+                                const lepus::Value& properties) override {}
+  void OnSetNativeProps(Element* ptr, const std::string& name,
+                        const std::string& value, bool is_style) override {}
+
+  std::map<lynx::devtool::DevToolFunction,
+           std::function<void(const base::any&)>>
+  GetDevToolFunction() override {
+    auto noop = [](const base::any&) {};
+    return {
+        {lynx::devtool::DevToolFunction::InitForInspector, noop},
+        {lynx::devtool::DevToolFunction::InitPlugForInspector, noop},
+        {lynx::devtool::DevToolFunction::InitStyleValueElement, noop},
+        {lynx::devtool::DevToolFunction::InitStyleRoot, noop},
+        {lynx::devtool::DevToolFunction::SetDocElement, noop},
+        {lynx::devtool::DevToolFunction::SetStyleValueElement, noop},
+        {lynx::devtool::DevToolFunction::SetStyleRoot, noop},
+    };
+  }
+
+  std::vector<Element*> added_nodes;
+};
+
 bool LayoutBundleHasResetStyle(
     const std::unique_ptr<LayoutBundle>& layout_bundle, CSSPropertyID id) {
   if (layout_bundle == nullptr) {
@@ -10207,6 +10243,38 @@ TEST_P(FiberElementTest, CreateTypedPageTemplateMaterializesRoot) {
   EXPECT_EQ(page_template->result_->children()[0].get(), child.get());
 }
 
+TEST_P(FiberElementTest, CreateTypedPageTemplateNotifiesInspectorRoot) {
+  auto observer = std::make_shared<RecordingInspectorElementObserver>();
+  manager->SetInspectorElementObserver(observer);
+  manager->dom_tree_enabled_ = true;
+
+  auto lepus_ctx = runtime::MTSRuntime::CreateContext(
+      runtime::ContextType::LepusNGContextType);
+  ASSERT_TRUE(lepus_ctx);
+  lepus_ctx->Initialize();
+  lepus_ctx->SetGlobalData(
+      BASE_STATIC_STRING(tasm::kTemplateAssembler),
+      lepus::Value(static_cast<runtime::MTSRuntime::Delegate*>(tasm.get())));
+  auto* mts_ctx = runtime::MTSRuntime::ToQuickContext(lepus_ctx.get());
+  ASSERT_TRUE(mts_ctx);
+
+  lepus::Value create_args[] = {lepus::Value("page"), lepus::Value(),
+                                lepus::Value(), lepus::Value("0")};
+  auto created_value = RendererFunctions::FiberCreateTypedElementTemplate(
+      mts_ctx, create_args, 4);
+
+  ASSERT_TRUE(created_value.IsRefCounted());
+  auto page_template =
+      fml::static_ref_ptr_cast<TemplateElement>(created_value.RefCounted())
+          .strongify();
+  ASSERT_NE(page_template, nullptr);
+  ASSERT_NE(manager->root(), nullptr);
+  ASSERT_EQ(observer->added_nodes.size(), 1u);
+  EXPECT_EQ(observer->added_nodes[0], manager->root());
+  EXPECT_NE(observer->added_nodes[0], page_template.get());
+  EXPECT_TRUE(observer->added_nodes[0]->is_page());
+}
+
 TEST_P(FiberElementTest, InsertTypedPageTemplateChildBeforeAutomaticFlush) {
   auto lepus_ctx = runtime::MTSRuntime::CreateContext(
       runtime::ContextType::LepusNGContextType);

core/runtime/lepus/bindings/renderer_functions.cc

@@ -3674,15 +3674,20 @@ RENDERER_FUNCTION_CC(FiberCreateTypedElementTemplate) {
   element->SetElementSlots(element_slots);
   element->SetOptions(options);
   element->SetUid(*arg3);
+  fml::RefPtr<FiberElement> typed_page_root = nullptr;
   if (arg0->String().IsEqual(kElementPageTag)) {
     // Page templates are root templates, so materialize the root eagerly while
     // still returning the TemplateElement shell for template APIs.
-    if (element->GetRoot() == nullptr) {
+    typed_page_root = element->GetRoot();
+    if (typed_page_root == nullptr) {
       RETURN_UNDEFINED();
     }
   }
 
   ON_NODE_CREATE(element);
+  if (typed_page_root != nullptr) {
+    ON_NODE_ADDED(typed_page_root);
+  }
 
   RETURN(lepus::Value(element));
 }