IntersectionObserver: make exceptions match spec

third_party/WebKit/Source/bindings/core/v8/custom/V8IntersectionObserverCustom.cpp

Index: third_party/WebKit/Source/bindings/core/v8/custom/V8IntersectionObserverCustom.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/custom/V8IntersectionObserverCustom.cpp b/third_party/WebKit/Source/bindings/core/v8/custom/V8IntersectionObserverCustom.cpp
index c6bbfce265b1d4c344b28ada36ae9e81e7ac32a7..44e91b46258e11c907af4b410bdc4f94bf9fdb9b 100644
--- a/third_party/WebKit/Source/bindings/core/v8/custom/V8IntersectionObserverCustom.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/custom/V8IntersectionObserverCustom.cpp
@@ -36,15 +36,15 @@ void V8IntersectionObserver::constructorCustom(const v8::FunctionCallbackInfo<v8
     IntersectionObserverInit intersectionObserverInit;
     ExceptionState exceptionState(ExceptionState::ConstructionContext, "Intersection", info.Holder(), info.GetIsolate());
     V8IntersectionObserverInit::toImpl(info.GetIsolate(), info[1], intersectionObserverInit, exceptionState);
-    if (exceptionState.hadException()) {
-        V8ThrowException::throwGeneralError(info.GetIsolate(), exceptionState.message());
+    if (exceptionState.throwIfNeeded())
         return;
-    }
 
     IntersectionObserverCallback* callback = new V8IntersectionObserverCallback(v8::Local<v8::Function>::Cast(info[0]), wrapper, ScriptState::current(info.GetIsolate()));
     IntersectionObserver* observer = IntersectionObserver::create(intersectionObserverInit, *callback, exceptionState);
-    if (!observer || exceptionState.hadException()) {
-        V8ThrowException::throwGeneralError(info.GetIsolate(), exceptionState.message());
+    if (exceptionState.throwIfNeeded())
+        return;
+    if (!observer) {
+        V8ThrowException::throwGeneralError(info.GetIsolate(), "Unknown error while constructing IntersectionObserver.");
         return;
     }