Move hasPendingActivity from ActiveDOMObject to ScriptWrappable

third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp b/third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp
index 908535a2b661cab50b0fe854a9a53dfb043f663b..0a4ff7833ab65ace85072c2abc2603fb5854d232 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8GCController.cpp
@@ -30,6 +30,7 @@
 
 #include "bindings/core/v8/V8GCController.h"
 
+#include "bindings/core/v8/NPV8Object.h"
 #include "bindings/core/v8/RetainedDOMInfo.h"
 #include "bindings/core/v8/V8AbstractEventListener.h"
 #include "bindings/core/v8/V8Binding.h"
@@ -121,11 +122,8 @@ public:
         v8::Local<v8::Object> wrapper = v8::Local<v8::Object>::New(m_isolate, v8::Persistent<v8::Object>::Cast(*value));
         ASSERT(V8DOMWrapper::hasInternalFieldsSet(wrapper));
         const WrapperTypeInfo* type = toWrapperTypeInfo(wrapper);
-        ActiveDOMObject* activeDOMObject = type->toActiveDOMObject(wrapper);
-        if (activeDOMObject && activeDOMObject->hasPendingActivity()) {
-            v8::Persistent<v8::Object>::Cast(*value).MarkActive();
+        if (type != npObjectTypeInfo() && toScriptWrappable(wrapper)->hasPendingActivity())
             return;
-        }
 
         if (classId == WrapperTypeInfo::NodeClassId) {
             ASSERT(V8Node::hasInstance(wrapper, m_isolate));
@@ -179,8 +177,7 @@ public:
 
         const WrapperTypeInfo* type = toWrapperTypeInfo(wrapper);
 
-        ActiveDOMObject* activeDOMObject = type->toActiveDOMObject(wrapper);
-        if (activeDOMObject && activeDOMObject->hasPendingActivity()) {
+        if (type != npObjectTypeInfo() && toScriptWrappable(wrapper)->hasPendingActivity()) {
             m_isolate->SetObjectGroupId(*value, liveRootId());
             ++m_domObjectsWithPendingActivity;
         }
@@ -459,4 +456,49 @@ void V8GCController::traceDOMWrappers(v8::Isolate* isolate, Visitor* visitor)
     isolate->VisitHandlesWithClassIds(&tracer);
 }
 
+class PendingActivityVisitor : public v8::PersistentHandleVisitor {
+public:
+    explicit PendingActivityVisitor(ExecutionContext* executionContext)
+        : m_executionContext(executionContext)
+        , m_pendingActivityFound(false)
+    {
+    }
+
+    void VisitPersistentHandle(v8::Persistent<v8::Value>* value, uint16_t classId) override
+    {

[kinuko, 2016/01/25 04:06:25]

Could we count how many # of handles this class visited and report it as a UMA
so that we can take a look at it while it's in Canary & whenever we have
performance concern?

[haraken, 2016/01/25 04:08:42]

Sounds nice. Will do.

+        // If we have already found any wrapper that has a pending activity,
+        // we don't need to check other wrappers.
+        if (m_pendingActivityFound)

[kinuko, 2016/01/25 04:06:25]

Would there be a way to exit the visitor loop once we found pending activity? 
...looks like we need v8 change which may not be worth doing unless we see perf
issue.

[haraken, 2016/01/25 04:08:42]

Yeah, in the current V8 API, we don't have a way to exit the loop earlier :/

+            return;
+
+        if (classId != WrapperTypeInfo::NodeClassId && classId != WrapperTypeInfo::ObjectClassId)
+            return;
+
+        const v8::Persistent<v8::Object>& wrapper = v8::Persistent<v8::Object>::Cast(*value);
+        const WrapperTypeInfo* type = toWrapperTypeInfo(wrapper);
+        // The ExecutionContext check is heavy, so it should be done at the last.
+        if (type != npObjectTypeInfo()
+            && toScriptWrappable(wrapper)->hasPendingActivity()
+            /* && toExecutionContext(v8::Object::CreationContext(wrapper)) == m_executionContext */

[haraken, 2016/01/22 17:15:44]

To enable this condition, I need to implement the V8 API (i.e.,
v8::Object::CreationContext). I'll do that before landing this CL.

(Note: Even if we don't enable the condition, it will not affect the correctness
-- it will just delay collecting a worker object of compositor workers, where
multiple ExecutionContexts are associated with one isolate.)

+            )
+            m_pendingActivityFound = true;
+    }
+
+    bool pendingActivityFound() const { return m_pendingActivityFound; }
+
+private:
+    RawPtrWillBePersistent<ExecutionContext> m_executionContext;
+    bool m_pendingActivityFound;
+};
+
+bool V8GCController::hasPendingActivity(ExecutionContext* executionContext)
+{
+    // V8GCController::hasPendingActivity is used only when a worker checks if
+    // the worker contains any wrapper that has pending activities.
+    ASSERT(!isMainThread());
+    PendingActivityVisitor visitor(executionContext);
+    toIsolate(executionContext)->VisitHandlesWithClassIds(&visitor);
+    return visitor.pendingActivityFound();
+}
+
 } // namespace blink