Use v8::MicrotasksScope internally in V8RecursionScope.

If this sticks we can just remove V8RecursionScope and WebScopedMicrotaskSuppression,
along with other cleanups.

BUG=585949

Review URL: https://codereview.chromium.org/1743763004

Cr-Commit-Position: refs/heads/master@{#379574}

24 files changed, 106 insertions, 169 deletions

diff --git a/chrome/test/base/v8_unit_test.cc b/chrome/test/base/v8_unit_test.cc
index 9f52f06..392ff45 100644
--- a/chrome/test/base/v8_unit_test.cc
+++ b/chrome/test/base/v8_unit_test.cc
@@ -11,6 +11,7 @@
 #include "base/strings/stringprintf.h"
 #include "chrome/common/chrome_paths.h"
 #include "third_party/WebKit/public/web/WebKit.h"
+#include "third_party/WebKit/public/web/WebScopedMicrotaskSuppression.h"
 
 namespace {
 
@@ -95,6 +96,7 @@ bool V8UnitTest::RunJavascriptTestF(const std::string& test_fixture,
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   v8::Local<v8::Value> function_property =
       context->Global()->Get(v8::String::NewFromUtf8(isolate, "runTest"));
@@ -209,6 +211,7 @@ void V8UnitTest::ExecuteScriptInContext(const base::StringPiece& script_source,
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
   v8::Local<v8::String> source =
       v8::String::NewFromUtf8(isolate,
                               script_source.data(),
@@ -257,6 +260,7 @@ void V8UnitTest::TestFunction(const std::string& function_name) {
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   v8::Local<v8::Value> function_property = context->Global()->Get(
       v8::String::NewFromUtf8(isolate, function_name.c_str()));
diff --git a/content/child/v8_value_converter_impl_unittest.cc b/content/child/v8_value_converter_impl_unittest.cc
index 311fa7f..435ea30 100644
--- a/content/child/v8_value_converter_impl_unittest.cc
+++ b/content/child/v8_value_converter_impl_unittest.cc
@@ -14,6 +14,7 @@
 #include "base/values.h"
 #include "content/child/v8_value_converter_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/public/web/WebScopedMicrotaskSuppression.h"
 #include "v8/include/v8.h"
 
 namespace content {
@@ -287,6 +288,7 @@ TEST_F(V8ValueConverterImplTest, ObjectExceptions) {
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate_, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   // Set up objects to throw when reading or writing 'foo'.
   const char* source =
@@ -329,6 +331,7 @@ TEST_F(V8ValueConverterImplTest, ArrayExceptions) {
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate_, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   const char* source = "(function() {"
       "var arr = [];"
@@ -405,6 +408,7 @@ TEST_F(V8ValueConverterImplTest, Prototype) {
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate_, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   const char* source = "(function() {"
       "Object.prototype.foo = 'foo';"
@@ -429,6 +433,7 @@ TEST_F(V8ValueConverterImplTest, StripNullFromObjects) {
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate_, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   const char* source = "(function() {"
       "return { foo: undefined, bar: null };"
@@ -487,6 +492,7 @@ TEST_F(V8ValueConverterImplTest, WeirdProperties) {
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate_, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   const char* source = "(function() {"
       "return {"
@@ -525,6 +531,7 @@ TEST_F(V8ValueConverterImplTest, ArrayGetters) {
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate_, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   const char* source = "(function() {"
       "var a = [0];"
@@ -549,6 +556,7 @@ TEST_F(V8ValueConverterImplTest, UndefinedValueBehavior) {
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate_, context_);
   v8::Context::Scope context_scope(context);
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
 
   v8::Local<v8::Object> object;
   {
diff --git a/content/renderer/pepper/v8_var_converter_unittest.cc b/content/renderer/pepper/v8_var_converter_unittest.cc
index cd07abb..e030ffd 100644
--- a/content/renderer/pepper/v8_var_converter_unittest.cc
+++ b/content/renderer/pepper/v8_var_converter_unittest.cc
@@ -29,6 +29,7 @@
 #include "ppapi/shared_impl/var.h"
 #include "ppapi/shared_impl/var_tracker.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/public/web/WebScopedMicrotaskSuppression.h"
 #include "v8/include/v8.h"
 
 using ppapi::ArrayBufferVar;
@@ -403,6 +404,7 @@ TEST_F(V8VarConverterTest, StrangeDictionaryKeyTest) {
     v8::Local<v8::Context> context =
         v8::Local<v8::Context>::New(isolate_, context_);
     v8::Context::Scope context_scope(context);
+    blink::WebScopedMicrotaskSuppression microtasks_scope;
 
     const char* source =
         "(function() {"
diff --git a/extensions/renderer/activity_log_converter_strategy_unittest.cc b/extensions/renderer/activity_log_converter_strategy_unittest.cc
index 9237cad..aa80447 100644
--- a/extensions/renderer/activity_log_converter_strategy_unittest.cc
+++ b/extensions/renderer/activity_log_converter_strategy_unittest.cc
@@ -6,6 +6,7 @@
 #include "base/values.h"
 #include "extensions/renderer/activity_log_converter_strategy.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/public/web/WebScopedMicrotaskSuppression.h"
 #include "v8/include/v8.h"
 
 using content::V8ValueConverter;
@@ -122,6 +123,7 @@ TEST_F(ActivityLogConverterStrategyTest, ConversionTest) {
       "};"
       "})();";
 
+  blink::WebScopedMicrotaskSuppression microtasks_scope;
   v8::Local<v8::Script> script(
       v8::Script::Compile(v8::String::NewFromUtf8(isolate_, source)));
   v8::Local<v8::Object> v8_object = script->Run().As<v8::Object>();
diff --git a/extensions/renderer/api_test_base.cc b/extensions/renderer/api_test_base.cc
index abf868b..79f95e2 100644
--- a/extensions/renderer/api_test_base.cc
+++ b/extensions/renderer/api_test_base.cc
@@ -214,7 +214,7 @@ void ApiTestEnvironment::RunTestInner(const std::string& test_name,
 }
 
 void ApiTestEnvironment::RunPromisesAgain() {
-  env()->isolate()->RunMicrotasks();
+  v8::MicrotasksScope::PerformCheckpoint(env()->isolate());
   base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(&ApiTestEnvironment::RunPromisesAgain,
                             base::Unretained(this)));
diff --git a/extensions/renderer/module_system_test.cc b/extensions/renderer/module_system_test.cc
index 68c4bd1..06a4d55 100644
--- a/extensions/renderer/module_system_test.cc
+++ b/extensions/renderer/module_system_test.cc
@@ -253,7 +253,7 @@ void ModuleSystemTest::ExpectNoAssertionsMade() {
 }
 
 void ModuleSystemTest::RunResolvedPromises() {
-  isolate_->RunMicrotasks();
+  v8::MicrotasksScope::PerformCheckpoint(isolate_);
 }
 
 }  // namespace extensions
diff --git a/extensions/renderer/safe_builtins.cc b/extensions/renderer/safe_builtins.cc
index 3bfa01a..3a66eaf 100644
--- a/extensions/renderer/safe_builtins.cc
+++ b/extensions/renderer/safe_builtins.cc
@@ -9,6 +9,7 @@
 #include "base/strings/stringprintf.h"
 #include "extensions/renderer/script_context.h"
 #include "extensions/renderer/v8_helpers.h"
+#include "third_party/WebKit/public/web/WebScopedMicrotaskSuppression.h"
 
 namespace extensions {
 
@@ -200,6 +201,7 @@ class ExtensionImpl : public v8::Extension {
         return;
     }
 
+    blink::WebScopedMicrotaskSuppression microtasks_scope;
     v8::Local<v8::Value> return_value;
     if (function->Call(context, recv, argc, argv.get()).ToLocal(&return_value))
       info.GetReturnValue().Set(return_value);
diff --git a/gin/run_microtasks_observer.cc b/gin/run_microtasks_observer.cc
index f453a66..0ca0078 100644
--- a/gin/run_microtasks_observer.cc
+++ b/gin/run_microtasks_observer.cc
@@ -15,7 +15,7 @@ void RunMicrotasksObserver::WillProcessTask(const base::PendingTask& task) {
 
 void RunMicrotasksObserver::DidProcessTask(const base::PendingTask& task) {
   v8::Isolate::Scope scope(isolate_);
-  isolate_->RunMicrotasks();
+  v8::MicrotasksScope::PerformCheckpoint(isolate_);
 }
 
 }  // namespace gin
diff --git a/gin/run_microtasks_observer.h b/gin/run_microtasks_observer.h
index 7f1431f..ca160be 100644
--- a/gin/run_microtasks_observer.h
+++ b/gin/run_microtasks_observer.h
@@ -12,7 +12,7 @@ namespace gin {
 
 // Runs any pending v8 Microtasks each time a task is completed.
 // TODO(hansmuller); At some point perhaps this can be replaced with
-// the (currently experimental) Isolate::SetAutorunMicrotasks() method.
+// the (currently experimental) v8::MicrotasksPolicy::kAuto method.
 
 class RunMicrotasksObserver : public base::MessageLoop::TaskObserver {
  public:
diff --git a/third_party/WebKit/Source/bindings/core/v8/ReadableStreamOperationsTest.cpp b/third_party/WebKit/Source/bindings/core/v8/ReadableStreamOperationsTest.cpp
index a76e6d0..49ddfe5 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ReadableStreamOperationsTest.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ReadableStreamOperationsTest.cpp
@@ -12,6 +12,7 @@
 #include "bindings/core/v8/V8BindingForTesting.h"
 #include "bindings/core/v8/V8BindingMacros.h"
 #include "bindings/core/v8/V8IteratorResultValue.h"
+#include "bindings/core/v8/V8RecursionScope.h"
 #include "bindings/core/v8/V8ThrowException.h"
 #include "core/dom/Document.h"
 #include "core/streams/ReadableStreamController.h"
@@ -138,7 +139,7 @@ public:
     ~ReadableStreamOperationsTest() override
     {
         // Execute all pending microtasks
-        isolate()->RunMicrotasks();
+        v8::MicrotasksScope::PerformCheckpoint(isolate());
         EXPECT_FALSE(m_block.HasCaught());
     }
 
@@ -149,6 +150,7 @@ public:
     {
         v8::Local<v8::String> source;
         v8::Local<v8::Script> script;
+        V8RecursionScope::MicrotaskSuppression microtasks(isolate());
         if (!v8Call(v8::String::NewFromUtf8(isolate(), s, v8::NewStringType::kNormal), source)) {
             ADD_FAILURE();
             return ScriptValue();
@@ -253,12 +255,12 @@ TEST_F(ReadableStreamOperationsTest, Read)
         Function::createFunction(scriptState(), it2),
         NotReached::createFunction(scriptState()));
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_FALSE(it1->isSet());
     EXPECT_FALSE(it2->isSet());
 
     ASSERT_FALSE(evalWithPrintingError("controller.enqueue('hello')").isEmpty());
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_TRUE(it1->isSet());
     EXPECT_TRUE(it1->isValid());
     EXPECT_FALSE(it1->isDone());
@@ -266,7 +268,7 @@ TEST_F(ReadableStreamOperationsTest, Read)
     EXPECT_FALSE(it2->isSet());
 
     ASSERT_FALSE(evalWithPrintingError("controller.close()").isEmpty());
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_TRUE(it1->isSet());
     EXPECT_TRUE(it1->isValid());
     EXPECT_FALSE(it1->isDone());
@@ -309,7 +311,7 @@ TEST_F(ReadableStreamOperationsTest, CreateReadableStreamWithCustomUnderlyingSou
     ReadableStreamOperations::read(scriptState(), reader).then(Function::createFunction(scriptState(), it2), NotReached::createFunction(scriptState()));
     ReadableStreamOperations::read(scriptState(), reader).then(Function::createFunction(scriptState(), it3), NotReached::createFunction(scriptState()));
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ(10, underlyingSource->desiredSize());
 
@@ -326,7 +328,7 @@ TEST_F(ReadableStreamOperationsTest, CreateReadableStreamWithCustomUnderlyingSou
     EXPECT_FALSE(it3->isSet());
 
     underlyingSource->close();
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(it3->isSet());
     EXPECT_TRUE(it3->isValid());
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyTest.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyTest.cpp
index 34f2d7c..f6601dd 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyTest.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptPromisePropertyTest.cpp
@@ -281,7 +281,7 @@ TEST_F(ScriptPromisePropertyGarbageCollectedTest, Resolve_ResolvesScriptPromise)
     property()->resolve(value);
     EXPECT_EQ(Property::Resolved, property()->getState());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ(1u, nResolveCalls);
     EXPECT_EQ(1u, nOtherResolveCalls);
     EXPECT_EQ(wrap(mainWorld(), value), actual);
@@ -307,7 +307,7 @@ TEST_F(ScriptPromisePropertyGarbageCollectedTest, ResolveAndGetPromiseOnOtherWor
     property()->resolve(value);
     EXPECT_EQ(Property::Resolved, property()->getState());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ(1u, nResolveCalls);
     EXPECT_EQ(0u, nOtherResolveCalls);
 
@@ -316,7 +316,7 @@ TEST_F(ScriptPromisePropertyGarbageCollectedTest, ResolveAndGetPromiseOnOtherWor
         otherPromise.then(stub(currentScriptState(), otherActual, nOtherResolveCalls), notReached(currentScriptState()));
     }
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ(1u, nResolveCalls);
     EXPECT_EQ(1u, nOtherResolveCalls);
     EXPECT_EQ(wrap(mainWorld(), value), actual);
@@ -343,7 +343,7 @@ TEST_F(ScriptPromisePropertyGarbageCollectedTest, Reject_RejectsScriptPromise)
         property()->promise(otherWorld()).then(notReached(currentScriptState()), stub(currentScriptState(), otherActual, nOtherRejectCalls));
     }
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ(1u, nRejectCalls);
     EXPECT_EQ(wrap(mainWorld(), reason), actual);
     EXPECT_EQ(1u, nOtherRejectCalls);
@@ -374,7 +374,7 @@ TEST_F(ScriptPromisePropertyGarbageCollectedTest, Resolve_DeadContext)
     property()->resolve(new GarbageCollectedScriptWrappable("value"));
     EXPECT_EQ(Property::Pending, property()->getState());
 
-    v8::Isolate::GetCurrent()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(v8::Isolate::GetCurrent());
 }
 
 TEST_F(ScriptPromisePropertyGarbageCollectedTest, Reset)
@@ -405,7 +405,7 @@ TEST_F(ScriptPromisePropertyGarbageCollectedTest, Reset)
     EXPECT_EQ(0u, nOldResolveCalls);
     EXPECT_EQ(0u, nNewRejectCalls);
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ(1u, nOldResolveCalls);
     EXPECT_EQ(1u, nNewRejectCalls);
     EXPECT_NE(oldPromise, newPromise);
@@ -445,7 +445,7 @@ TEST_F(ScriptPromisePropertyRefCountedTest, Resolve)
     property()->resolve(value.get());
     EXPECT_EQ(Property::Resolved, property()->getState());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ(1u, nResolveCalls);
     EXPECT_EQ(wrap(mainWorld(), value), actual);
 }
@@ -464,7 +464,7 @@ TEST_F(ScriptPromisePropertyRefCountedTest, Reject)
     property()->reject(reason);
     EXPECT_EQ(Property::Rejected, property()->getState());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ(1u, nRejectCalls);
     EXPECT_EQ(wrap(mainWorld(), reason), actual);
 }
@@ -514,7 +514,7 @@ public:
             property->promise(DOMWrapperWorld::mainWorld()).then(stub(currentScriptState(), actualValue, nResolveCalls), notReached(currentScriptState()));
         }
         property->resolve(value);
-        isolate()->RunMicrotasks();
+        v8::MicrotasksScope::PerformCheckpoint(isolate());
         {
             ScriptState::Scope scope(mainScriptState());
             actual = toCoreString(actualValue.v8Value()->ToString(mainScriptState()->context()).ToLocalChecked());
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptPromiseResolverTest.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptPromiseResolverTest.cpp
index b6cf586..1c946d9 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptPromiseResolverTest.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptPromiseResolverTest.cpp
@@ -60,7 +60,7 @@ public:
         createClosure(callback, v8::Undefined(isolate()), isolate());
 
         // Execute all pending microtasks
-        isolate()->RunMicrotasks();
+        v8::MicrotasksScope::PerformCheckpoint(isolate());
     }
 
     OwnPtr<DummyPageHolder> m_pageHolder;
@@ -96,7 +96,7 @@ TEST_F(ScriptPromiseResolverTest, resolve)
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ(String(), onRejected);
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ(String(), onRejected);
@@ -111,14 +111,14 @@ TEST_F(ScriptPromiseResolverTest, resolve)
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ(String(), onRejected);
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ("hello", onFulfilled);
     EXPECT_EQ(String(), onRejected);
 
     resolver->resolve("bye");
     resolver->reject("bye");
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ("hello", onFulfilled);
     EXPECT_EQ(String(), onRejected);
@@ -144,7 +144,7 @@ TEST_F(ScriptPromiseResolverTest, reject)
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ(String(), onRejected);
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ(String(), onRejected);
@@ -159,14 +159,14 @@ TEST_F(ScriptPromiseResolverTest, reject)
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ(String(), onRejected);
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ("hello", onRejected);
 
     resolver->resolve("bye");
     resolver->reject("bye");
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ("hello", onRejected);
@@ -196,7 +196,7 @@ TEST_F(ScriptPromiseResolverTest, stop)
     }
 
     resolver->resolve("hello");
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ(String(), onRejected);
@@ -321,7 +321,7 @@ TEST_F(ScriptPromiseResolverTest, resolveVoid)
     }
 
     resolver->resolve();
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ("undefined", onFulfilled);
     EXPECT_EQ(String(), onRejected);
@@ -345,7 +345,7 @@ TEST_F(ScriptPromiseResolverTest, rejectVoid)
     }
 
     resolver->reject();
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ(String(), onFulfilled);
     EXPECT_EQ("undefined", onRejected);
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptPromiseTest.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptPromiseTest.cpp
index 5c3fec7..01d144e 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptPromiseTest.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptPromiseTest.cpp
@@ -83,7 +83,7 @@ public:
         createClosure(callback, v8::Undefined(m_scope.isolate()), m_scope.isolate());
 
         // Execute all pending microtasks
-        isolate()->RunMicrotasks();
+        v8::MicrotasksScope::PerformCheckpoint(isolate());
     }
 
     String toString(const ScriptValue& value)
@@ -124,13 +124,13 @@ TEST_F(ScriptPromiseTest, thenResolve)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     resolver.resolve(v8String(isolate(), "hello"));
 
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ("hello", toString(onFulfilled));
     EXPECT_TRUE(onRejected.isEmpty());
@@ -148,7 +148,7 @@ TEST_F(ScriptPromiseTest, resolveThen)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ("hello", toString(onFulfilled));
     EXPECT_TRUE(onRejected.isEmpty());
@@ -165,13 +165,13 @@ TEST_F(ScriptPromiseTest, thenReject)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     resolver.reject(v8String(isolate(), "hello"));
 
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_EQ("hello", toString(onRejected));
@@ -189,7 +189,7 @@ TEST_F(ScriptPromiseTest, rejectThen)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_EQ("hello", toString(onRejected));
@@ -226,7 +226,7 @@ TEST_F(ScriptPromiseTest, castNonPromise)
     EXPECT_TRUE(onRejected1.isEmpty());
     EXPECT_TRUE(onRejected2.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ("hello", toString(onFulfilled1));
     EXPECT_EQ("hello", toString(onFulfilled2));
@@ -248,7 +248,7 @@ TEST_F(ScriptPromiseTest, reject)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_EQ("hello", toString(onRejected));
@@ -264,7 +264,7 @@ TEST_F(ScriptPromiseTest, rejectWithExceptionState)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_EQ("SyntaxError: some syntax error", toString(onRejected));
@@ -282,7 +282,7 @@ TEST_F(ScriptPromiseTest, allWithEmptyPromises)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_FALSE(onFulfilled.isEmpty());
     EXPECT_TRUE(toStringArray(onFulfilled).isEmpty());
@@ -304,7 +304,7 @@ TEST_F(ScriptPromiseTest, allWithResolvedPromises)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_FALSE(onFulfilled.isEmpty());
     Vector<String> values = toStringArray(onFulfilled);
@@ -329,7 +329,7 @@ TEST_F(ScriptPromiseTest, allWithRejectedPromise)
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_TRUE(onRejected.isEmpty());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(onFulfilled.isEmpty());
     EXPECT_FALSE(onRejected.isEmpty());
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp b/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
index 04de69e..f0a8dfd 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8Initializer.cpp
@@ -321,7 +321,7 @@ static void initializeV8Common(v8::Isolate* isolate)
 
     v8::Debug::SetLiveEditEnabled(isolate, false);
 
-    isolate->SetAutorunMicrotasks(false);
+    isolate->SetMicrotasksPolicy(v8::MicrotasksPolicy::kScoped);
 }
 
 namespace {
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp b/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp
index 0a2cfcb..65c02bc 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.cpp
@@ -30,7 +30,6 @@
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8HiddenValue.h"
 #include "bindings/core/v8/V8ObjectConstructor.h"
-#include "bindings/core/v8/V8RecursionScope.h"
 #include "bindings/core/v8/V8ScriptRunner.h"
 #include "core/frame/Deprecation.h"
 #include "core/inspector/MainThreadDebugger.h"
@@ -53,18 +52,6 @@ static void microtasksCompletedCallback(v8::Isolate* isolate)
     V8PerIsolateData::from(isolate)->runEndOfScopeTasks();
 }
 
-#if ENABLE(ASSERT)
-static void assertV8RecursionScope(v8::Isolate* isolate)
-{
-    ASSERT(V8RecursionScope::properlyUsed(isolate));
-}
-
-static bool runningUnitTest()
-{
-    return Platform::current()->unitTestSupport();
-}
-#endif
-
 static void useCounterCallback(v8::Isolate* isolate, v8::Isolate::UseCounterFeature feature)
 {
     UseCounter::Feature blinkFeature;
@@ -143,25 +130,15 @@ static void useCounterCallback(v8::Isolate* isolate, v8::Isolate::UseCounterFeat
 }
 
 V8PerIsolateData::V8PerIsolateData()
-    : m_destructionPending(false)
-    , m_isolateHolder(adoptPtr(new gin::IsolateHolder()))
+    : m_isolateHolder(adoptPtr(new gin::IsolateHolder()))
     , m_stringCache(adoptPtr(new StringCache(isolate())))
     , m_hiddenValue(V8HiddenValue::create())
     , m_constructorMode(ConstructorMode::CreateNewObject)
-    , m_recursionLevel(0)
     , m_isHandlingRecursionLevelError(false)
     , m_isReportingException(false)
-#if ENABLE(ASSERT)
-    , m_internalScriptRecursionLevel(0)
-#endif
-    , m_performingMicrotaskCheckpoint(false)
 {
     // FIXME: Remove once all v8::Isolate::GetCurrent() calls are gone.
     isolate()->Enter();
-#if ENABLE(ASSERT)
-    if (!runningUnitTest())
-        isolate()->AddCallCompletedCallback(&assertV8RecursionScope);
-#endif
     isolate()->AddBeforeCallEnteredCallback(&beforeCallEnteredCallback);
     isolate()->AddMicrotasksCompletedCallback(&microtasksCompletedCallback);
     if (isMainThread())
@@ -206,9 +183,6 @@ void V8PerIsolateData::willBeDestroyed(v8::Isolate* isolate)
 {
     V8PerIsolateData* data = from(isolate);
 
-    ASSERT(!data->m_destructionPending);
-    data->m_destructionPending = true;
-
     data->m_threadDebugger.clear();
     // Clear any data that may have handles into the heap,
     // prior to calling ThreadState::detach().
@@ -219,10 +193,6 @@ void V8PerIsolateData::willBeDestroyed(v8::Isolate* isolate)
 // gets called but before the Isolate exits.
 void V8PerIsolateData::destroy(v8::Isolate* isolate)
 {
-#if ENABLE(ASSERT)
-    if (!runningUnitTest())
-        isolate->RemoveCallCompletedCallback(&assertV8RecursionScope);
-#endif
     isolate->RemoveBeforeCallEnteredCallback(&beforeCallEnteredCallback);
     isolate->RemoveMicrotasksCompletedCallback(&microtasksCompletedCallback);
     V8PerIsolateData* data = from(isolate);
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.h b/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.h
index 5d709e7..33ed8dc 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.h
+++ b/third_party/WebKit/Source/bindings/core/v8/V8PerIsolateData.h
@@ -74,31 +74,18 @@ public:
 
     static void enableIdleTasks(v8::Isolate*, PassOwnPtr<gin::V8IdleTaskRunner>);
 
-    bool destructionPending() const { return m_destructionPending; }
     v8::Isolate* isolate() { return m_isolateHolder->isolate(); }
 
     StringCache* stringCache() { return m_stringCache.get(); }
 
     v8::Persistent<v8::Value>& ensureLiveRoot();
 
-    int recursionLevel() const { return m_recursionLevel; }
-    int incrementRecursionLevel() { return ++m_recursionLevel; }
-    int decrementRecursionLevel() { return --m_recursionLevel; }
     bool isHandlingRecursionLevelError() const { return m_isHandlingRecursionLevelError; }
     void setIsHandlingRecursionLevelError(bool value) { m_isHandlingRecursionLevelError = value; }
 
     bool isReportingException() const { return m_isReportingException; }
     void setReportingException(bool value) { m_isReportingException = value; }
 
-    bool performingMicrotaskCheckpoint() const { return m_performingMicrotaskCheckpoint; }
-    void setPerformingMicrotaskCheckpoint(bool performingMicrotaskCheckpoint) { m_performingMicrotaskCheckpoint = performingMicrotaskCheckpoint; }
-
-#if ENABLE(ASSERT)
-    int internalScriptRecursionLevel() const { return m_internalScriptRecursionLevel; }
-    int incrementInternalScriptRecursionLevel() { return ++m_internalScriptRecursionLevel; }
-    int decrementInternalScriptRecursionLevel() { return --m_internalScriptRecursionLevel; }
-#endif
-
     V8HiddenValue* hiddenValue() { return m_hiddenValue.get(); }
 
     v8::Local<v8::FunctionTemplate> domTemplate(const void* domTemplateKey, v8::FunctionCallback = 0, v8::Local<v8::Value> data = v8::Local<v8::Value>(), v8::Local<v8::Signature> = v8::Local<v8::Signature>(), int length = 0);
@@ -131,7 +118,6 @@ private:
     bool hasInstance(const WrapperTypeInfo* untrusted, v8::Local<v8::Value>, DOMTemplateMap&);
     v8::Local<v8::Object> findInstanceInPrototypeChain(const WrapperTypeInfo*, v8::Local<v8::Value>, DOMTemplateMap&);
 
-    bool m_destructionPending;
     OwnPtr<gin::IsolateHolder> m_isolateHolder;
     DOMTemplateMap m_domTemplateMapForMainWorld;
     DOMTemplateMap m_domTemplateMapForNonMainWorld;
@@ -143,15 +129,9 @@ private:
     bool m_constructorMode;
     friend class ConstructorMode;
 
-    int m_recursionLevel;
     bool m_isHandlingRecursionLevelError;
     bool m_isReportingException;
 
-#if ENABLE(ASSERT)
-    int m_internalScriptRecursionLevel;
-#endif
-    bool m_performingMicrotaskCheckpoint;
-
     Vector<OwnPtr<EndOfScopeTask>> m_endOfScopeTasks;
     OwnPtr<ThreadDebugger> m_threadDebugger;
 };
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8RecursionScope.cpp b/third_party/WebKit/Source/bindings/core/v8/V8RecursionScope.cpp
index ed10e86..b4c3acf 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8RecursionScope.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8RecursionScope.cpp
@@ -30,13 +30,6 @@
 
 #include "bindings/core/v8/V8RecursionScope.h"
 
-#include "core/dom/Microtask.h"
-
 namespace blink {
 
-void V8RecursionScope::didLeaveScriptContext()
-{
-    Microtask::performCheckpoint(m_isolate);
-}
-
 } // namespace blink
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8RecursionScope.h b/third_party/WebKit/Source/bindings/core/v8/V8RecursionScope.h
index dd9a51f..8bbd26c 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8RecursionScope.h
+++ b/third_party/WebKit/Source/bindings/core/v8/V8RecursionScope.h
@@ -59,63 +59,39 @@ class CORE_EXPORT V8RecursionScope {
     STACK_ALLOCATED();
 public:
     explicit V8RecursionScope(v8::Isolate* isolate)
-        : m_isolate(isolate)
+        : m_scope(isolate, v8::MicrotasksScope::kRunMicrotasks)
     {
-        V8PerIsolateData::from(m_isolate)->incrementRecursionLevel();
-        // If you want V8 to autorun microtasks, this class needs to have a
-        // v8::Isolate::SuppressMicrotaskExecutionScope member.
-        ASSERT(!isolate->WillAutorunMicrotasks());
+        ASSERT(isolate->GetMicrotasksPolicy() == v8::MicrotasksPolicy::kScoped);
     }
 
     ~V8RecursionScope()
     {
-        if (!V8PerIsolateData::from(m_isolate)->decrementRecursionLevel())
-            didLeaveScriptContext();
     }
 
     static int recursionLevel(v8::Isolate* isolate)
     {
-        return V8PerIsolateData::from(isolate)->recursionLevel();
+        return v8::MicrotasksScope::GetCurrentDepth(isolate);
     }
 
-#if ENABLE(ASSERT)
-    static bool properlyUsed(v8::Isolate* isolate)
-    {
-        return recursionLevel(isolate) > 0 || V8PerIsolateData::from(isolate)->internalScriptRecursionLevel() > 0;
-    }
-#endif
-
     class MicrotaskSuppression {
         USING_FAST_MALLOC(MicrotaskSuppression);
         WTF_MAKE_NONCOPYABLE(MicrotaskSuppression);
     public:
-        MicrotaskSuppression(v8::Isolate* isolate)
-#if ENABLE(ASSERT)
-            : m_isolate(isolate)
-#endif
+        explicit MicrotaskSuppression(v8::Isolate* isolate)
+            : m_scope(isolate, v8::MicrotasksScope::kDoNotRunMicrotasks)
         {
-#if ENABLE(ASSERT)
-            V8PerIsolateData::from(m_isolate)->incrementInternalScriptRecursionLevel();
-#endif
         }
 
         ~MicrotaskSuppression()
         {
-#if ENABLE(ASSERT)
-            V8PerIsolateData::from(m_isolate)->decrementInternalScriptRecursionLevel();
-#endif
         }
 
     private:
-#if ENABLE(ASSERT)
-        v8::Isolate* m_isolate;
-#endif
+        v8::MicrotasksScope m_scope;
     };
 
 private:
-    void didLeaveScriptContext();
-
-    v8::Isolate* m_isolate;
+    v8::MicrotasksScope m_scope;
 };
 
 } // namespace blink
diff --git a/third_party/WebKit/Source/core/dom/Microtask.cpp b/third_party/WebKit/Source/core/dom/Microtask.cpp
index 488c577..9e57c77 100644
--- a/third_party/WebKit/Source/core/dom/Microtask.cpp
+++ b/third_party/WebKit/Source/core/dom/Microtask.cpp
@@ -40,13 +40,9 @@ namespace blink {
 
 void Microtask::performCheckpoint(v8::Isolate* isolate)
 {
-    V8PerIsolateData* isolateData = V8PerIsolateData::from(isolate);
-    ASSERT(isolateData);
-    if (isolateData->recursionLevel() || isolateData->performingMicrotaskCheckpoint() || isolateData->destructionPending() || ScriptForbiddenScope::isScriptForbidden())
+    if (ScriptForbiddenScope::isScriptForbidden())
         return;
-    isolateData->setPerformingMicrotaskCheckpoint(true);
-    isolate->RunMicrotasks();
-    isolateData->setPerformingMicrotaskCheckpoint(false);
+    v8::MicrotasksScope::PerformCheckpoint(isolate);
 }
 
 static void microtaskFunctionCallback(void* data)
diff --git a/third_party/WebKit/Source/core/streams/ReadableStreamReaderTest.cpp b/third_party/WebKit/Source/core/streams/ReadableStreamReaderTest.cpp
index f7e12f8..352a30f 100644
--- a/third_party/WebKit/Source/core/streams/ReadableStreamReaderTest.cpp
+++ b/third_party/WebKit/Source/core/streams/ReadableStreamReaderTest.cpp
@@ -179,7 +179,7 @@ TEST_F(ReadableStreamReaderTest, Release)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_EQ("AbortError: the reader is already released", onRejected);
 
@@ -208,7 +208,7 @@ TEST_F(ReadableStreamReaderTest, ReadAfterRelease)
 
     EXPECT_FALSE(result.isSet);
     EXPECT_TRUE(onRejected.isNull());
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_FALSE(result.isSet);
     EXPECT_EQ("TypeError: the reader is already released", onRejected);
@@ -250,7 +250,7 @@ TEST_F(ReadableStreamReaderTest, EnqueueThenRead)
     EXPECT_FALSE(result.isSet);
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(result.isSet);
     EXPECT_FALSE(result.isDone);
@@ -264,7 +264,7 @@ TEST_F(ReadableStreamReaderTest, EnqueueThenRead)
     EXPECT_FALSE(result2.isSet);
     EXPECT_TRUE(onRejected2.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(result2.isSet);
     EXPECT_FALSE(result2.isDone);
@@ -290,7 +290,7 @@ TEST_F(ReadableStreamReaderTest, ReadThenEnqueue)
     EXPECT_FALSE(result2.isSet);
     EXPECT_TRUE(onRejected2.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_FALSE(result.isSet);
     EXPECT_TRUE(onRejected.isNull());
@@ -298,7 +298,7 @@ TEST_F(ReadableStreamReaderTest, ReadThenEnqueue)
     EXPECT_TRUE(onRejected2.isNull());
 
     m_stream->enqueue("hello");
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(result.isSet);
     EXPECT_FALSE(result.isDone);
@@ -308,7 +308,7 @@ TEST_F(ReadableStreamReaderTest, ReadThenEnqueue)
     EXPECT_TRUE(onRejected2.isNull());
 
     m_stream->enqueue("world");
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(result2.isSet);
     EXPECT_FALSE(result2.isDone);
@@ -330,7 +330,7 @@ TEST_F(ReadableStreamReaderTest, ClosedReader)
     String onClosedFulfilled, onClosedRejected;
     ReadResult result;
     String onReadRejected;
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     reader->closed(scriptState()).then(createCaptor(&onClosedFulfilled), createCaptor(&onClosedRejected));
     reader->read(scriptState()).then(createResultCaptor(&result), createCaptor(&onReadRejected));
     EXPECT_TRUE(onClosedFulfilled.isNull());
@@ -338,7 +338,7 @@ TEST_F(ReadableStreamReaderTest, ClosedReader)
     EXPECT_FALSE(result.isSet);
     EXPECT_TRUE(onReadRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ("undefined", onClosedFulfilled);
     EXPECT_TRUE(onClosedRejected.isNull());
     EXPECT_TRUE(result.isSet);
@@ -361,7 +361,7 @@ TEST_F(ReadableStreamReaderTest, ErroredReader)
 
     String onClosedFulfilled, onClosedRejected;
     String onReadFulfilled, onReadRejected;
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     reader->closed(scriptState()).then(createCaptor(&onClosedFulfilled), createCaptor(&onClosedRejected));
     reader->read(scriptState()).then(createCaptor(&onReadFulfilled), createCaptor(&onReadRejected));
     EXPECT_TRUE(onClosedFulfilled.isNull());
@@ -369,7 +369,7 @@ TEST_F(ReadableStreamReaderTest, ErroredReader)
     EXPECT_TRUE(onReadFulfilled.isNull());
     EXPECT_TRUE(onReadRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_TRUE(onClosedFulfilled.isNull());
     EXPECT_EQ("SyntaxError: some error", onClosedRejected);
     EXPECT_TRUE(onReadFulfilled.isNull());
@@ -389,7 +389,7 @@ TEST_F(ReadableStreamReaderTest, PendingReadsShouldBeResolvedWhenClosed)
     reader->read(scriptState()).then(createResultCaptor(&result), createCaptor(&onRejected));
     reader->read(scriptState()).then(createResultCaptor(&result2), createCaptor(&onRejected2));
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_FALSE(result.isSet);
     EXPECT_TRUE(onRejected.isNull());
     EXPECT_FALSE(result2.isSet);
@@ -401,7 +401,7 @@ TEST_F(ReadableStreamReaderTest, PendingReadsShouldBeResolvedWhenClosed)
     EXPECT_FALSE(result2.isSet);
     EXPECT_TRUE(onRejected2.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(result.isSet);
     EXPECT_TRUE(result.isDone);
@@ -427,7 +427,7 @@ TEST_F(ReadableStreamReaderTest, PendingReadsShouldBeRejectedWhenErrored)
     reader->read(scriptState()).then(createCaptor(&onFulfilled), createCaptor(&onRejected));
     reader->read(scriptState()).then(createCaptor(&onFulfilled2), createCaptor(&onRejected2));
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
     EXPECT_TRUE(onFulfilled2.isNull());
@@ -439,7 +439,7 @@ TEST_F(ReadableStreamReaderTest, PendingReadsShouldBeRejectedWhenErrored)
     EXPECT_TRUE(onFulfilled2.isNull());
     EXPECT_TRUE(onRejected2.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_EQ(onRejected, "SyntaxError: some error");
@@ -460,7 +460,7 @@ TEST_F(ReadableStreamReaderTest, PendingReadsShouldBeResolvedWhenCanceled)
     reader->read(scriptState()).then(createResultCaptor(&result), createCaptor(&onRejected));
     reader->read(scriptState()).then(createResultCaptor(&result2), createCaptor(&onRejected2));
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_FALSE(result.isSet);
     EXPECT_TRUE(onRejected.isNull());
     EXPECT_FALSE(result2.isSet);
@@ -473,7 +473,7 @@ TEST_F(ReadableStreamReaderTest, PendingReadsShouldBeResolvedWhenCanceled)
     EXPECT_FALSE(result2.isSet);
     EXPECT_TRUE(onRejected2.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(result.isSet);
     EXPECT_TRUE(result.isDone);
@@ -502,7 +502,7 @@ TEST_F(ReadableStreamReaderTest, CancelShouldNotWorkWhenNotActive)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_EQ("TypeError: the reader is already released", onRejected);
@@ -528,7 +528,7 @@ TEST_F(ReadableStreamReaderTest, Cancel)
     EXPECT_TRUE(onCancelFulfilled.isNull());
     EXPECT_TRUE(onCancelRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ("undefined", onClosedFulfilled);
     EXPECT_TRUE(onClosedRejected.isNull());
     EXPECT_EQ("undefined", onCancelFulfilled);
@@ -552,7 +552,7 @@ TEST_F(ReadableStreamReaderTest, Close)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ("undefined", onFulfilled);
     EXPECT_TRUE(onRejected.isNull());
     EXPECT_FALSE(exceptionState.hadException());
@@ -574,7 +574,7 @@ TEST_F(ReadableStreamReaderTest, Error)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_EQ("SyntaxError: some error", onRejected);
     EXPECT_FALSE(exceptionState.hadException());
diff --git a/third_party/WebKit/Source/core/streams/ReadableStreamTest.cpp b/third_party/WebKit/Source/core/streams/ReadableStreamTest.cpp
index fb52f46..031ecdd 100644
--- a/third_party/WebKit/Source/core/streams/ReadableStreamTest.cpp
+++ b/third_party/WebKit/Source/core/streams/ReadableStreamTest.cpp
@@ -304,7 +304,7 @@ TEST_F(ReadableStreamTest, CloseWhenReadable)
 
     stream->read(scriptState());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_EQ(ReadableStream::Readable, stream->stateInternal());
     EXPECT_FALSE(stream->isPulling());
@@ -335,7 +335,7 @@ TEST_F(ReadableStreamTest, CancelWhenClosed)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ("undefined", onFulfilled);
     EXPECT_TRUE(onRejected.isNull());
 }
@@ -358,7 +358,7 @@ TEST_F(ReadableStreamTest, CancelWhenErrored)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_EQ("NotFoundError: error", onRejected);
 }
@@ -392,7 +392,7 @@ TEST_F(ReadableStreamTest, CancelWhenReadable)
     EXPECT_TRUE(onCancelFulfilled.isNull());
     EXPECT_TRUE(onCancelRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ("undefined", onCancelFulfilled);
     EXPECT_TRUE(onCancelRejected.isNull());
 }
@@ -416,7 +416,7 @@ TEST_F(ReadableStreamTest, CancelWhenLocked)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
 
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_EQ("TypeError: this stream is locked to a ReadableStreamReader", onRejected);
@@ -563,7 +563,7 @@ TEST_F(ReadableStreamTest, GetClosedReader)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_EQ("undefined", onFulfilled);
     EXPECT_TRUE(onRejected.isNull());
 }
@@ -586,7 +586,7 @@ TEST_F(ReadableStreamTest, GetErroredReader)
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_TRUE(onRejected.isNull());
 
-    isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(isolate());
     EXPECT_TRUE(onFulfilled.isNull());
     EXPECT_EQ("SyntaxError: some error", onRejected);
 }
diff --git a/third_party/WebKit/Source/modules/cachestorage/CacheTest.cpp b/third_party/WebKit/Source/modules/cachestorage/CacheTest.cpp
index 7834ae9..1c4030c 100644
--- a/third_party/WebKit/Source/modules/cachestorage/CacheTest.cpp
+++ b/third_party/WebKit/Source/modules/cachestorage/CacheTest.cpp
@@ -249,7 +249,7 @@ public:
     {
         ScriptValue onReject;
         promise.then(UnreachableFunction::create(scriptState()), TestFunction::create(scriptState(), &onReject));
-        isolate()->RunMicrotasks();
+        v8::MicrotasksScope::PerformCheckpoint(isolate());
         return onReject;
     }
 
@@ -263,7 +263,7 @@ public:
     {
         ScriptValue onResolve;
         promise.then(TestFunction::create(scriptState(), &onResolve), UnreachableFunction::create(scriptState()));
-        isolate()->RunMicrotasks();
+        v8::MicrotasksScope::PerformCheckpoint(isolate());
         return onResolve;
     }
 
diff --git a/third_party/WebKit/Source/modules/fetch/ReadableStreamDataConsumerHandleTest.cpp b/third_party/WebKit/Source/modules/fetch/ReadableStreamDataConsumerHandleTest.cpp
index 9a9daea..fba225c 100644
--- a/third_party/WebKit/Source/modules/fetch/ReadableStreamDataConsumerHandleTest.cpp
+++ b/third_party/WebKit/Source/modules/fetch/ReadableStreamDataConsumerHandleTest.cpp
@@ -8,6 +8,7 @@
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/V8BindingMacros.h"
 #include "bindings/core/v8/V8GCController.h"
+#include "bindings/core/v8/V8RecursionScope.h"
 #include "core/dom/Document.h"
 #include "core/testing/DummyPageHolder.h"
 #include "modules/fetch/DataConsumerHandleTestUtil.h"
@@ -59,6 +60,7 @@ public:
     {
         v8::Local<v8::String> source;
         v8::Local<v8::Script> script;
+        V8RecursionScope::MicrotaskSuppression microtasks(isolate());
         if (!v8Call(v8::String::NewFromUtf8(isolate(), s, v8::NewStringType::kNormal), source)) {
             ADD_FAILURE();
             return v8::MaybeLocal<v8::Value>();
diff --git a/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerContainerTest.cpp b/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerContainerTest.cpp
index 8c0af13..cb4e2da 100644
--- a/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerContainerTest.cpp
+++ b/third_party/WebKit/Source/modules/serviceworkers/ServiceWorkerContainerTest.cpp
@@ -92,7 +92,7 @@ void expectRejected(ScriptState* scriptState, ScriptPromise& promise, const Scri
 {
     StubScriptFunction resolved, rejected;
     promise.then(resolved.function(scriptState), rejected.function(scriptState));
-    promise.isolate()->RunMicrotasks();
+    v8::MicrotasksScope::PerformCheckpoint(promise.isolate());
     EXPECT_EQ(0ul, resolved.callCount());
     EXPECT_EQ(1ul, rejected.callCount());
     if (rejected.callCount())