Oilpan: move BaseChooserOnlyDateAndTimeInputType to the heap.

third_party/WebKit/Source/core/html/forms/DateInputType.h

Index: third_party/WebKit/Source/core/html/forms/DateInputType.h
diff --git a/third_party/WebKit/Source/core/html/forms/DateInputType.h b/third_party/WebKit/Source/core/html/forms/DateInputType.h
index 38002ce531509436d7675bec9462eda2f673991d..473649336a2e8e41a28babfffd6f0fb0540b6c73 100644
--- a/third_party/WebKit/Source/core/html/forms/DateInputType.h
+++ b/third_party/WebKit/Source/core/html/forms/DateInputType.h
@@ -43,11 +43,14 @@ using BaseDateInputType = BaseChooserOnlyDateAndTimeInputType;
 #endif
 
 class DateInputType final : public BaseDateInputType {
+    WILL_BE_USING_DATETIMERCHOOSERCLIENT_GC_MIXIN(DateInputType);

[haraken, 2015/11/22 01:01:39]

Help me understand: Why can't we make BaseChooserOnlyDateAndTimeInputType a GC
mixin instead of making DateInputType a GC mixin? It seems more straightforward
since the DateTimeChooserClient is inherited by
BaseChooserOnlyDateAndTimeInputType.

[sof, 2015/11/22 07:48:55]

Isn't it the rule that the leftmost base should define itself as a GC mixin?

[haraken, 2015/11/22 14:27:09]

I think the rule is as follows.

  class A : public GarbageCollectedMixin { };
  class B : public GarbageCollected<B> { };
  class C : public B, public A { };
  class D : public C { };

We need the USING_GARBAGE_COLLECTED_MIXIN for C but don't need it for D. Am I
wrong?

 public:
     static PassRefPtrWillBeRawPtr<InputType> create(HTMLInputElement&);
+    DEFINE_BASEDATEANDTIMEINPUTTYPE_VIRTUAL_TRACE(BaseDateInputType);
 
 private:
-    DateInputType(HTMLInputElement&);
+    explicit DateInputType(HTMLInputElement&);
+
     void countUsage() override;
     const AtomicString& formControlType() const override;
     StepRange createStepRange(AnyStepHandling) const override;