v8binding: Minor refactoring of ActiveScriptWrappable.

ActiveScriptWrappable is designed to be inherited.  The ctor should
be protected:.

Also all classes that support virtual member functions should have
the virtual dtor.

Change-Id: I1eaa60b45607b5404868e0d293a150e1b98dfc5b
Reviewed-on: https://chromium-review.googlesource.com/964068Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Yuki Shiino <yukishiino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543343}

third_party/WebKit/Source/bindings/core/v8/ActiveScriptWrappable.h

@@ -17,9 +17,11 @@ class ActiveScriptWrappable : public ActiveScriptWrappableBase {
   WTF_MAKE_NONCOPYABLE(ActiveScriptWrappable);
 
  public:
-  ActiveScriptWrappable() = default;
+  ~ActiveScriptWrappable() override = default;
 
  protected:
+  ActiveScriptWrappable() = default;
+
   bool IsContextDestroyed() const final {
     const auto* execution_context =
         static_cast<const T*>(this)->GetExecutionContext();

third_party/WebKit/Source/platform/bindings/ActiveScriptWrappableBase.cpp

@@ -12,13 +12,6 @@
 
 namespace blink {
 
-ActiveScriptWrappableBase::ActiveScriptWrappableBase() {
-  DCHECK(ThreadState::Current());
-  v8::Isolate* isolate = ThreadState::Current()->GetIsolate();
-  V8PerIsolateData* isolate_data = V8PerIsolateData::From(isolate);
-  isolate_data->AddActiveScriptWrappable(this);
-}
-
 void ActiveScriptWrappableBase::TraceActiveScriptWrappables(
     v8::Isolate* isolate,
     ScriptWrappableVisitor* visitor) {
@@ -57,4 +50,11 @@ void ActiveScriptWrappableBase::TraceActiveScriptWrappables(
   }
 }
 
+ActiveScriptWrappableBase::ActiveScriptWrappableBase() {
+  DCHECK(ThreadState::Current());
+  v8::Isolate* isolate = ThreadState::Current()->GetIsolate();
+  V8PerIsolateData* isolate_data = V8PerIsolateData::From(isolate);
+  isolate_data->AddActiveScriptWrappable(this);
+}
+
 }  // namespace blink

third_party/WebKit/Source/platform/bindings/ActiveScriptWrappableBase.h

@@ -8,10 +8,7 @@
 #include "platform/PlatformExport.h"
 #include "platform/heap/Handle.h"
 #include "platform/wtf/Noncopyable.h"
-
-namespace v8 {
-class Isolate;
-}
+#include "v8/include/v8.h"
 
 namespace blink {
 
@@ -27,12 +24,14 @@ class PLATFORM_EXPORT ActiveScriptWrappableBase : public GarbageCollectedMixin {
   WTF_MAKE_NONCOPYABLE(ActiveScriptWrappableBase);
 
  public:
-  ActiveScriptWrappableBase();
-
   static void TraceActiveScriptWrappables(v8::Isolate*,
                                           ScriptWrappableVisitor*);
 
+  virtual ~ActiveScriptWrappableBase() = default;
+
  protected:
+  ActiveScriptWrappableBase();
+
   virtual bool IsContextDestroyed() const = 0;
   virtual bool DispatchHasPendingActivity() const = 0;
   virtual ScriptWrappable* ToScriptWrappable() = 0;