diff --git a/src/gn/analyzer_unittest.cc b/src/gn/analyzer_unittest.cc
index 5952562..dfd1486 100644
--- a/src/gn/analyzer_unittest.cc
+++ b/src/gn/analyzer_unittest.cc
@@ -15,7 +15,6 @@
 #include "gn/source_file.h"
 #include "gn/substitution_list.h"
 #include "gn/target.h"
-#include "gn/test_with_scheduler.h"
 #include "gn/tool.h"
 #include "gn/toolchain.h"
 #include "util/test/test.h"
@@ -44,7 +43,7 @@
   ~MockLoader() override = default;
 };
 
-class AnalyzerTest : public TestWithScheduler {
+class AnalyzerTest : public testing::Test {
  public:
   AnalyzerTest()
       : loader_(new MockLoader),
@@ -91,8 +90,6 @@
 
   void RunAnalyzerTest(const std::string& input,
                        const std::string& expected_output) {
-    // Wait for any async OnResolve() to happen.
-    scheduler().Run();
     Analyzer analyzer(builder_, SourceFile("//build/config/BUILDCONFIG.gn"),
                       SourceFile("//.gn"),
                       {SourceFile("//out/debug/args.gn"),
diff --git a/src/gn/builder.cc b/src/gn/builder.cc
index bf47b13..1f3ecd8 100644
--- a/src/gn/builder.cc
+++ b/src/gn/builder.cc
@@ -236,9 +236,6 @@
       for (auto* bad_record : bad_records) {
         depstring +=
             "\n\"" + bad_record->label().GetUserVisibleName(true) + "\"";
-        if (records_resolving_on_worker_.contains(bad_record)) {
-          depstring += " (currently resolving on worker)";
-        }
       }
       *err = Err(Location(), "", depstring);
     } else {
@@ -500,7 +497,6 @@
 
   if (record->type() == BuilderRecord::ITEM_TARGET) {
     Target* target = record->item()->AsTarget();
-    // All deps must be resolved before OnResolved can be called.
     if (!ResolveDeps(&target->public_deps(), err) ||
         !ResolveDeps(&target->private_deps(), err) ||
         !ResolveDeps(&target->data_deps(), err) ||
@@ -509,10 +505,6 @@
         !ResolveConfigs(&target->public_configs(), err) ||
         !ResolvePool(target, err) || !ResolveToolchain(target, err))
       return false;
-
-    // Offload Target::OnResolved to a worker thread.
-    ScheduleTargetOnResolve(record);
-    return true;
   } else if (record->type() == BuilderRecord::ITEM_CONFIG) {
     Config* config = record->item()->AsConfig();
     if (!ResolveConfigs(&config->configs(), err))
@@ -524,47 +516,11 @@
     if (!ResolvePools(toolchain, err))
       return false;
   }
-  if (!record->item()->OnResolved(err))
-    return false;
 
-  return CompleteItemResolution(record, err);
-}
-
-void Builder::ScheduleTargetOnResolve(BuilderRecord* record) {
-  DCHECK(g_scheduler);
-  bool already_existed = !records_resolving_on_worker_.add(record);
-  DCHECK(!already_existed);
-
-  g_scheduler->IncrementWorkCount();
-  g_scheduler->ScheduleWork([this, record]() {
-    Err err;
-    bool success = record->item()->AsTarget()->OnResolved(&err);
-    DCHECK(success == !err.has_error());
-
-    g_scheduler->task_runner()->PostTask(
-        [this, record, err]() {
-          CompleteAsyncTargetResolution(record, err);
-        });
-  });
-}
-
-void Builder::CompleteAsyncTargetResolution(
-    BuilderRecord* record, const Err& err) {
-  records_resolving_on_worker_.erase(record);
-  if (err.has_error()) {
-    g_scheduler->FailWithError(err);
-  } else {
-    Err next_err;
-    if (!CompleteItemResolution(record, &next_err)) {
-      g_scheduler->FailWithError(next_err);
-    }
-  }
-  g_scheduler->DecrementWorkCount();
-}
-
-bool Builder::CompleteItemResolution(BuilderRecord* record, Err* err) {
   record->set_resolved(true);
 
+  if (!record->item()->OnResolved(err))
+    return false;
   if (record->should_generate() && resolved_and_generated_callback_)
     resolved_and_generated_callback_(record);
 
diff --git a/src/gn/builder.h b/src/gn/builder.h
index e4d996c..a9c01aa 100644
--- a/src/gn/builder.h
+++ b/src/gn/builder.h
@@ -13,7 +13,6 @@
 #include "gn/builder_record_map.h"
 #include "gn/label.h"
 #include "gn/label_ptr.h"
-#include "gn/pointer_set.h"
 #include "gn/unique_vector.h"
 
 class ActionValues;
@@ -122,9 +121,6 @@
   // This takes a BuilderRecord with resolved dependencies, and fills in the
   // target's Label*Vectors with the resolved pointers.
   bool ResolveItem(BuilderRecord* record, Err* err);
-  void ScheduleTargetOnResolve(BuilderRecord* record);
-  void CompleteAsyncTargetResolution(BuilderRecord* record, const Err& err);
-  bool CompleteItemResolution(BuilderRecord* record, Err* err);
 
   // Fills in the pointers in the given vector based on the labels. We assume
   // that everything should be resolved by this point, so will return an error
@@ -148,8 +144,6 @@
 
   ResolvedGeneratedCallback resolved_and_generated_callback_;
 
-  PointerSet<const BuilderRecord> records_resolving_on_worker_;
-
   Builder(const Builder&) = delete;
   Builder& operator=(const Builder&) = delete;
 };
diff --git a/src/gn/builder_unittest.cc b/src/gn/builder_unittest.cc
index 59b58f8..59068a6 100644
--- a/src/gn/builder_unittest.cc
+++ b/src/gn/builder_unittest.cc
@@ -166,7 +166,6 @@
   b->set_output_type(Target::SHARED_LIBRARY);
   b->visibility().SetPublic();
   builder_.ItemDefined(std::unique_ptr<Item>(b));
-  scheduler().Run();
 
   // B depends only on the already-loaded C and toolchain so we shouldn't have
   // requested anything else.
@@ -254,7 +253,6 @@
   a->public_deps().push_back(LabelTargetPair(b_label));
   a->set_output_type(Target::EXECUTABLE);
   builder_.ItemDefined(std::unique_ptr<Item>(a));
-  scheduler().Run();
 
   // A should have the generate bit set since it's in the default toolchain.
   BuilderRecord* a_record = builder_.GetRecord(a_label);
@@ -292,7 +290,6 @@
 
   Target* b = new Target(&settings2, b_label);
   b->set_output_type(Target::EXECUTABLE);
-  b->visibility().SetPublic();  // Allow 'a' to depend on 'b'
   b->gen_deps().push_back(LabelTargetPair(c_label));
   builder_.ItemDefined(std::unique_ptr<Item>(b));
 
@@ -308,7 +305,6 @@
   Target* d = new Target(&settings2, d_label);
   d->set_output_type(Target::EXECUTABLE);
   builder_.ItemDefined(std::unique_ptr<Item>(d));
-  scheduler().Run();
 
   BuilderRecord* a_record = builder_.GetRecord(a_label);
   BuilderRecord* b_record = builder_.GetRecord(b_label);
@@ -339,14 +335,12 @@
   Target* a = new Target(&settings_, a_label);
   a->gen_deps().push_back(LabelTargetPair(b_label));
   a->set_output_type(Target::EXECUTABLE);
-  a->visibility().SetPublic(); // Allow 'b' to depend on 'a'
   builder_.ItemDefined(std::unique_ptr<Item>(a));
 
   Target* b = new Target(&settings2, b_label);
   b->private_deps().push_back(LabelTargetPair(a_label));
   b->set_output_type(Target::EXECUTABLE);
   builder_.ItemDefined(std::unique_ptr<Item>(b));
-  scheduler().Run();
 
   Err err;
   EXPECT_TRUE(builder_.CheckForBadItems(&err));
diff --git a/src/gn/item.h b/src/gn/item.h
index 4a6e193..dd1a606 100644
--- a/src/gn/item.h
+++ b/src/gn/item.h
@@ -69,7 +69,6 @@
   // Called when this item is resolved, meaning it and all of its dependents
   // have no unresolved deps. Returns true on success. Sets the error and
   // returns false on failure.
-  // Can be called from any thread, so must not mutate dependencies.
   virtual bool OnResolved(Err* err);
 
  private:
diff --git a/src/gn/scheduler.cc b/src/gn/scheduler.cc
index 76d285c..6525f33 100644
--- a/src/gn/scheduler.cc
+++ b/src/gn/scheduler.cc
@@ -25,16 +25,6 @@
 }
 
 bool Scheduler::Run() {
-  // Reentrancy check.
-  CHECK(!is_running_);
-
-  // Ensure there is at least one task, (or else this will wait forever).
-  if (is_failed_ || (work_count_.IsZero() && pool_work_count_.IsZero())) {
-    return is_failed_;
-  }
-
-  has_been_shutdown_ = false;
-  is_running_ = true;
   main_thread_run_loop_->Run();
   bool local_is_failed;
   {
@@ -45,7 +35,6 @@
   // Don't do this while holding |lock_|, since it will block on the workers,
   // which may be in turn waiting on the lock.
   WaitForPoolTasks();
-  is_running_ = false;
   return !local_is_failed;
 }
 
diff --git a/src/gn/scheduler.h b/src/gn/scheduler.h
index b90814f..cf29fe8 100644
--- a/src/gn/scheduler.h
+++ b/src/gn/scheduler.h
@@ -140,9 +140,6 @@
   // loop.
   bool has_been_shutdown_ = false;
 
-  // Prevent reentrancy.
-  bool is_running_ = false;
-
   // Protected by the lock. See the corresponding Add/Get functions above.
   std::vector<base::FilePath> gen_dependencies_;
   std::vector<SourceFile> written_files_;