Port InspectorDomAgent to InspectorAgentState fields.

InnerEnable does the actual work, but doesn't set the
flag, that only happens when enabled() is called (the
protocol method). It'd be ok to set it anyway, it doesn't
cause traffic on the wire, but I think it's a bit clearer
to protect against forgetting to set it with a DCHECK.
So this fixes the bug you pointed out when reviewing
https://chromium-review.googlesource.com/c/chromium/src/+/1162931
and keeps the change seperate.

Bug: 851762
Change-Id: Ibd65a7e69539a760af6499be3f5ff96df6b3912b
Reviewed-on: https://chromium-review.googlesource.com/1163808
Commit-Queue: Johannes Henkel <johannes@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580978}

third_party/blink/renderer/core/inspector/inspector_dom_agent.cc

@@ -90,10 +90,6 @@ using namespace HTMLNames;
 using protocol::Maybe;
 using protocol::Response;
 
-namespace DOMAgentState {
-static const char kDomAgentEnabled[] = "domAgentEnabled";
-};
-
 namespace {
 
 const size_t kMaxTextSize = 10000;
@@ -242,14 +238,14 @@ InspectorDOMAgent::InspectorDOMAgent(
       dom_listener_(nullptr),
       document_node_to_id_map_(new NodeToIdMap()),
       last_node_id_(1),
-      suppress_attribute_modified_event_(false) {}
+      suppress_attribute_modified_event_(false),
+      enabled_(&agent_state_, /*default_value=*/false) {}
 
 InspectorDOMAgent::~InspectorDOMAgent() = default;
 
 void InspectorDOMAgent::Restore() {
-  if (!Enabled())
-    return;
-  InnerEnable();
+  if (enabled_.Get())
+    EnableAndReset();
 }
 
 HeapVector<Member<Document>> InspectorDOMAgent::Documents() {
@@ -274,7 +270,7 @@ void InspectorDOMAgent::SetDocument(Document* doc) {
   DiscardFrontendBindings();
   document_ = doc;
 
-  if (!Enabled())
+  if (!enabled_.Get())
     return;
 
   // Immediately communicate 0 document or document that has finished loading.
@@ -282,6 +278,10 @@ void InspectorDOMAgent::SetDocument(Document* doc) {
     GetFrontend()->documentUpdated();
 }
 
+bool InspectorDOMAgent::Enabled() const {
+  return enabled_.Get();
+}
+
 void InspectorDOMAgent::ReleaseDanglingNodes() {
   dangling_node_to_id_maps_.clear();
 }
@@ -448,8 +448,8 @@ Response InspectorDOMAgent::AssertEditableElement(int node_id,
   return Response::OK();
 }
 
-void InspectorDOMAgent::InnerEnable() {
-  state_->setBoolean(DOMAgentState::kDomAgentEnabled, true);
+void InspectorDOMAgent::EnableAndReset() {
+  enabled_.Set(true);
   history_ = new InspectorHistory();
   dom_editor_ = new DOMEditor(history_.Get());
   document_ = inspected_frames_->Root()->GetDocument();
@@ -457,19 +457,15 @@ void InspectorDOMAgent::InnerEnable() {
 }
 
 Response InspectorDOMAgent::enable() {
-  if (!Enabled())
-    InnerEnable();
+  if (!enabled_.Get())
+    EnableAndReset();
   return Response::OK();
 }
 
-bool InspectorDOMAgent::Enabled() const {
-  return state_->booleanProperty(DOMAgentState::kDomAgentEnabled, false);
-}
-
 Response InspectorDOMAgent::disable() {
-  if (!Enabled())
+  if (!enabled_.Get())
     return Response::Error("DOM agent hasn't been enabled");
-  state_->setBoolean(DOMAgentState::kDomAgentEnabled, false);
+  enabled_.Clear();
   instrumenting_agents_->removeInspectorDOMAgent(this);
   history_.Clear();
   dom_editor_.Clear();
@@ -482,8 +478,7 @@ Response InspectorDOMAgent::getDocument(
     Maybe<bool> pierce,
     std::unique_ptr<protocol::DOM::Node>* root) {
   // Backward compatibility. Mark agent as enabled when it requests document.
-  if (!Enabled())
-    InnerEnable();
+  enable();
 
   if (!document_)
     return Response::Error("Document is not available");
@@ -504,7 +499,7 @@ Response InspectorDOMAgent::getFlattenedDocument(
     Maybe<int> depth,
     Maybe<bool> pierce,
     std::unique_ptr<protocol::Array<protocol::DOM::Node>>* nodes) {
-  if (!Enabled())
+  if (!enabled_.Get())
     return Response::Error("DOM agent hasn't been enabled");
 
   if (!document_)
@@ -964,7 +959,7 @@ Response InspectorDOMAgent::performSearch(
     Maybe<bool> optional_include_user_agent_shadow_dom,
     String* search_id,
     int* result_count) {
-  if (!Enabled())
+  if (!enabled_.Get())
     return Response::Error("DOM agent is not enabled");
 
   // FIXME: Few things are missing here:
@@ -1224,7 +1219,7 @@ Response InspectorDOMAgent::moveTo(int node_id,
 }
 
 Response InspectorDOMAgent::undo() {
-  if (!Enabled())
+  if (!enabled_.Get())
     return Response::Error("DOM agent is not enabled");
   DummyExceptionStateForTesting exception_state;
   history_->Undo(exception_state);
@@ -1232,7 +1227,7 @@ Response InspectorDOMAgent::undo() {
 }
 
 Response InspectorDOMAgent::redo() {
-  if (!Enabled())
+  if (!enabled_.Get())
     return Response::Error("DOM agent is not enabled");
   DummyExceptionStateForTesting exception_state;
   history_->Redo(exception_state);
@@ -1317,7 +1312,7 @@ Response InspectorDOMAgent::getNodeForLocation(
     int y,
     Maybe<bool> optional_include_user_agent_shadow_dom,
     int* node_id) {
-  if (!Enabled())
+  if (!enabled_.Get())
     return Response::Error("DOM agent is not enabled");
   bool include_user_agent_shadow_dom =
       optional_include_user_agent_shadow_dom.fromMaybe(false);
@@ -1812,7 +1807,7 @@ void InspectorDOMAgent::DOMContentLoadedEventFired(LocalFrame* frame) {
 
   // Re-push document once it is loaded.
   DiscardFrontendBindings();
-  if (Enabled())
+  if (enabled_.Get())
     GetFrontend()->documentUpdated();
 }
 
@@ -2145,7 +2140,7 @@ Node* InspectorDOMAgent::NodeForPath(const String& path) {
 
 Response InspectorDOMAgent::pushNodeByPathToFrontend(const String& path,
                                                      int* node_id) {
-  if (!Enabled())
+  if (!enabled_.Get())
     return Response::Error("DOM agent is not enabled");
   if (Node* node = NodeForPath(path))
     *node_id = PushNodePathToFrontend(node);
@@ -2157,7 +2152,7 @@ Response InspectorDOMAgent::pushNodeByPathToFrontend(const String& path,
 Response InspectorDOMAgent::pushNodesByBackendIdsToFrontend(
     std::unique_ptr<protocol::Array<int>> backend_node_ids,
     std::unique_ptr<protocol::Array<int>>* result) {
-  if (!Enabled())
+  if (!enabled_.Get())
     return Response::Error("DOM agent is not enabled");
   *result = protocol::Array<int>::create();
   for (size_t index = 0; index < backend_node_ids->length(); ++index) {

third_party/blink/renderer/core/inspector/inspector_dom_agent.h

@@ -279,7 +279,9 @@ class CORE_EXPORT InspectorDOMAgent final
 
  private:
   void SetDocument(Document*);
-  void InnerEnable();
+  // Unconditionally enables the agent, even if |enabled_.Get()==true|.
+  // For idempotence, call enable().
+  void EnableAndReset();
 
   // Node-related methods.
   typedef HeapHashMap<Member<Node>, int> NodeToIdMap;
@@ -347,6 +349,7 @@ class CORE_EXPORT InspectorDOMAgent final
   Member<InspectorHistory> history_;
   Member<DOMEditor> dom_editor_;
   bool suppress_attribute_modified_event_;
+  InspectorAgentState::Boolean enabled_;
   DISALLOW_COPY_AND_ASSIGN(InspectorDOMAgent);
 };