Sync IntersectionObserver IDL with the spec

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

Index: third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp b/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
index 1970c981dc1e8de5d0fe50185daa80c0d5569d65..7da91ebc19173844a08fff4ebb5a47bbdc1fa91e 100644
--- a/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserver.cpp
@@ -102,12 +102,12 @@ void parseRootMargin(String rootMarginParameter, Vector<Length>& rootMargin, Exc
     }
 }
 
-void parseThresholds(const DoubleOrDoubleArray& thresholdParameter, Vector<float>& thresholds, ExceptionState& exceptionState)
+void parseThresholds(const DoubleOrDoubleSequence& thresholdParameter, Vector<float>& thresholds, ExceptionState& exceptionState)
 {
     if (thresholdParameter.isDouble()) {
         thresholds.append(static_cast<float>(thresholdParameter.getAsDouble()));
     } else {
-        for (auto thresholdValue : thresholdParameter.getAsDoubleArray())
+        for (auto thresholdValue : thresholdParameter.getAsDoubleSequence())
             thresholds.append(static_cast<float>(thresholdValue));
     }
 
@@ -148,16 +148,12 @@ IntersectionObserver* IntersectionObserver::create(const IntersectionObserverIni
     }
 
     Vector<Length> rootMargin;
-    if (observerInit.hasRootMargin())
-        parseRootMargin(observerInit.rootMargin(), rootMargin, exceptionState);
+    parseRootMargin(observerInit.rootMargin(), rootMargin, exceptionState);
     if (exceptionState.hadException())
         return nullptr;
 
     Vector<float> thresholds;
-    if (observerInit.hasThreshold())
-        parseThresholds(observerInit.threshold(), thresholds, exceptionState);
-    else
-        thresholds.append(0);
+    parseThresholds(observerInit.threshold(), thresholds, exceptionState);
     if (exceptionState.hadException())
         return nullptr;