Revert of Use intersection observer to control frame throttling

third_party/WebKit/Source/core/dom/IntersectionObserver.h

Index: third_party/WebKit/Source/core/dom/IntersectionObserver.h
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObserver.h b/third_party/WebKit/Source/core/dom/IntersectionObserver.h
index 3281fcea96352ef256fc00bd74383250e40b02ac..85c449675b38e35c07282ee23625347baf4eb16e 100644
--- a/third_party/WebKit/Source/core/dom/IntersectionObserver.h
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserver.h
@@ -32,15 +32,6 @@
   using EventCallback =
       Function<void(const HeapVector<Member<IntersectionObserverEntry>>&),
                WTF::SameThreadAffinity>;
-
-  // Defines the assumed initial state of the observed element. If the actual
-  // state is the same as the initial state, then no observation will be
-  // delivered. kAuto means the initial observation will always get sent.
-  enum class InitialState {
-    // TODO(skyostil): Add support for kVisible.
-    kAuto,
-    kHidden,
-  };
 
   static IntersectionObserver* create(const IntersectionObserverInit&,
                                       IntersectionObserverCallback&,
@@ -81,12 +72,6 @@
     return m_observations;
   }
 
-  // Set the assumed initial state of the observed element. Note that this can
-  // only be set before calling observe().
-  // TODO(skyostil): Move this setting to IntersectionObserverInit once the API
-  // is finalized.
-  void setInitialState(InitialState);
-
   DECLARE_TRACE();
 
  private:
@@ -105,7 +90,6 @@
   Length m_rightMargin;
   Length m_bottomMargin;
   Length m_leftMargin;
-  InitialState m_initialState;
 };
 
 }  // namespace blink