Add tests for trace wrappers

third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp

Index: third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..9df6b7cbba99e759e466aada2c683ed97119a905
--- /dev/null
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptWrappableVisitorTest.cpp
@@ -0,0 +1,147 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "bindings/core/v8/ScriptWrappableVisitor.h"
+
+#include "bindings/core/v8/ToV8.h"
+#include "bindings/core/v8/V8BindingForTesting.h"
+#include "bindings/core/v8/V8GCController.h"
+#include "bindings/core/v8/V8PerIsolateData.h"
+#include "core/testing/DeathAwareScriptWrappable.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+
+static void preciselyCollectGarbage()
+{
+    ThreadHeap::collectGarbage(BlinkGC::NoHeapPointersOnStack, BlinkGC::GCWithSweep, BlinkGC::ForcedGC);

[haraken, 2016/09/02 10:53:14]

Use collectAllGarbage to make sure that all garbage are collected.

[Marcel Hlopko, 2016/09/02 12:12:40]

Done.

+}
+
+static void runV8Scavenger(v8::Isolate* isolate)
+{
+    V8GCController::collectGarbage(isolate, true);
+}
+
+static void runV8FullGc(v8::Isolate* isolate)
+{
+    V8GCController::collectGarbage(isolate, false);
+}
+
+TEST(ScriptWrappableVisitorTest, OilpanCollectObjectsNotReachableFromV8)
+{
+    V8TestingScope scope;
+    v8::Isolate* isolate = scope.isolate();
+
+    {
+        v8::HandleScope handleScope(isolate);

[haraken, 2016/09/02 10:53:14]

You don't need to create a HandleScope since V8TestingScope creates it for you
:)

[Marcel Hlopko, 2016/09/02 12:12:40]

I actually do, I want the scope to be discarded and assert that the object was
collected.

+        DeathAwareScriptWrappable* object = DeathAwareScriptWrappable::create();
+        DeathAwareScriptWrappable::observeDeathsOf(object);
+
+        // Creates new V8 wrapper and associates it with global scope
+        toV8(object, scope.context()->Global(), isolate);
+    }
+
+    runV8Scavenger(isolate);
+    runV8FullGc(isolate);
+    preciselyCollectGarbage();
+
+    EXPECT_TRUE(DeathAwareScriptWrappable::hasDied());
+}
+
+TEST(ScriptWrappableVisitorTest, OilpanDoesntCollectObjectsReachableFromV8)
+{
+    V8TestingScope scope;
+    v8::Isolate* isolate = scope.isolate();
+    v8::HandleScope handleScope(isolate);
+    DeathAwareScriptWrappable* object = DeathAwareScriptWrappable::create();
+    DeathAwareScriptWrappable::observeDeathsOf(object);
+
+    // Creates new V8 wrapper and associates it with global scope
+    toV8(object, scope.context()->Global(), isolate);
+
+    runV8Scavenger(isolate);
+    runV8FullGc(isolate);
+    preciselyCollectGarbage();
+
+    EXPECT_FALSE(DeathAwareScriptWrappable::hasDied());
+}
+
+TEST(ScriptWrappableVisitorTest, V8ReportsLiveObjectsDuringScavenger)
+{
+    V8TestingScope scope;
+    v8::Isolate* isolate = scope.isolate();
+    v8::HandleScope handleScope(isolate);
+    DeathAwareScriptWrappable* object = DeathAwareScriptWrappable::create();
+    DeathAwareScriptWrappable::observeDeathsOf(object);
+
+    v8::Local<v8::Value> wrapper = toV8(
+        object, scope.context()->Global(), isolate);
+    EXPECT_TRUE(wrapper->IsObject());
+    v8::Local<v8::Object> wrapperObject = wrapper->ToObject();
+    // V8 collects wrappers with unmodified maps (as they can be recreated
+    // without loosing any data if needed). We need to create some property on
+    // wrapper so V8 will not see it as unmodified.
+    EXPECT_TRUE(wrapperObject->CreateDataProperty(scope.context(), 1, wrapper).IsJust());
+
+    runV8Scavenger(isolate);
+    preciselyCollectGarbage();
+
+    EXPECT_FALSE(DeathAwareScriptWrappable::hasDied());
+}
+
+TEST(ScriptWrappableVisitorTest, V8ReportsLiveObjectsDuringFullGc)
+{
+    V8TestingScope scope;
+    v8::Isolate* isolate = scope.isolate();
+    v8::HandleScope handleScope(isolate);
+    DeathAwareScriptWrappable* object = DeathAwareScriptWrappable::create();
+    DeathAwareScriptWrappable::observeDeathsOf(object);
+
+    toV8(object, scope.context()->Global(), isolate);
+
+    runV8Scavenger(isolate);
+    runV8FullGc(isolate);
+    preciselyCollectGarbage();
+
+    EXPECT_FALSE(DeathAwareScriptWrappable::hasDied());
+}
+
+TEST(ScriptWrappableVisitorTest, OilpanClearsHeadersWhenObjectDied)
+{
+    V8TestingScope scope;
+
+    DeathAwareScriptWrappable* object = DeathAwareScriptWrappable::create();
+    ScriptWrappableVisitor* visitor =
+        V8PerIsolateData::from(scope.isolate())->scriptWrappableVisitor();
+    auto header = HeapObjectHeader::fromPayload(object);
+    visitor->getHeadersToUnmark()->append(header);
+
+    preciselyCollectGarbage();
+
+    EXPECT_FALSE(visitor->getHeadersToUnmark()->contains(header));
+    visitor->getHeadersToUnmark()->clear();
+}
+
+TEST(ScriptWrappableVisitorTest, OilpanClearsMarkingDequeWhenObjectDied)
+{
+    V8TestingScope scope;
+
+    DeathAwareScriptWrappable* object = DeathAwareScriptWrappable::create();
+    ScriptWrappableVisitor* visitor =
+        V8PerIsolateData::from(scope.isolate())->scriptWrappableVisitor();
+    visitor->pushToMarkingDeque(
+        TraceTrait<DeathAwareScriptWrappable>::markWrapper,
+        TraceTrait<DeathAwareScriptWrappable>::heapObjectHeader,
+        object);
+
+    EXPECT_EQ(visitor->getMarkingDeque()->first().object(), object);
+
+    preciselyCollectGarbage();
+
+    EXPECT_EQ(visitor->getMarkingDeque()->first().object(), nullptr);
+    visitor->getMarkingDeque()->clear();
+    visitor->getVerifierDeque()->clear();
+}
+
+} // namespace blink