Event construction helpers should return Ref instead of PassRefPtr.
<https://webkit.org/b/139625>

Reviewed by Antti Koivisto.

Change all the FooEvent::create() construction helpers to return Ref<FooEvent>
instead of PassRefPtr<FooEvent>.

This allows the compiler to omit null checks at each call site, since we know
that these functions always return valid objects.

* Modules/airplay/WebKitPlaybackTargetAvailabilityEvent.h:
(WebCore::WebKitPlaybackTargetAvailabilityEvent::create):
* Modules/encryptedmedia/MediaKeyMessageEvent.h:
(WebCore::MediaKeyMessageEvent::create):
* Modules/encryptedmedia/MediaKeyNeededEvent.h:
(WebCore::MediaKeyNeededEvent::create):
* Modules/gamepad/GamepadEvent.h:
(WebCore::GamepadEvent::create):
* Modules/indexeddb/IDBVersionChangeEvent.h:
(WebCore::IDBVersionChangeEvent::create):
* Modules/indieui/UIRequestEvent.cpp:
(WebCore::UIRequestEvent::create):
* Modules/indieui/UIRequestEvent.h:
* Modules/mediastream/MediaStreamEvent.cpp:
(WebCore::MediaStreamEvent::create):
* Modules/mediastream/MediaStreamEvent.h:
* Modules/mediastream/MediaStreamTrackEvent.cpp:
(WebCore::MediaStreamTrackEvent::create):
* Modules/mediastream/MediaStreamTrackEvent.h:
* Modules/mediastream/RTCDTMFToneChangeEvent.cpp:
(WebCore::RTCDTMFToneChangeEvent::create):
* Modules/mediastream/RTCDTMFToneChangeEvent.h:
* Modules/mediastream/RTCDataChannelEvent.cpp:
(WebCore::RTCDataChannelEvent::create):
* Modules/mediastream/RTCDataChannelEvent.h:
* Modules/mediastream/RTCIceCandidateEvent.cpp:
(WebCore::RTCIceCandidateEvent::create):
* Modules/mediastream/RTCIceCandidateEvent.h:
* Modules/speech/SpeechSynthesisEvent.cpp:
(WebCore::SpeechSynthesisEvent::create):
* Modules/speech/SpeechSynthesisEvent.h:
* Modules/webaudio/AudioProcessingEvent.cpp:
(WebCore::AudioProcessingEvent::create):
* Modules/webaudio/AudioProcessingEvent.h:
* Modules/webaudio/OfflineAudioCompletionEvent.cpp:
(WebCore::OfflineAudioCompletionEvent::create):
* Modules/webaudio/OfflineAudioCompletionEvent.h:
* Modules/websockets/CloseEvent.h:
(WebCore::CloseEvent::create):
* dom/AnimationEvent.h:
* dom/AutocompleteErrorEvent.h:
* dom/BeforeLoadEvent.h:
* dom/BeforeTextInsertedEvent.h:
* dom/BeforeUnloadEvent.h:
* dom/ClipboardEvent.h:
* dom/CompositionEvent.h:
* dom/CustomEvent.h:
* dom/DeviceMotionEvent.h:
* dom/DeviceOrientationEvent.h:
* dom/ErrorEvent.h:
* dom/Event.h:
(WebCore::Event::create):
* dom/FocusEvent.h:
* dom/HashChangeEvent.h:
* dom/KeyboardEvent.h:
* dom/MessageEvent.h:
* dom/MouseEvent.cpp:
(WebCore::MouseEvent::create):
(WebCore::SimulatedMouseEvent::create):
* dom/MouseEvent.h:
(WebCore::MouseEvent::create):
* dom/MutationEvent.h:
* dom/OverflowEvent.h:
* dom/PageTransitionEvent.h:
* dom/PopStateEvent.cpp:
(WebCore::PopStateEvent::create):
* dom/PopStateEvent.h:
* dom/ProgressEvent.h:
(WebCore::ProgressEvent::create):
* dom/TextEvent.cpp:
(WebCore::TextEvent::create):
(WebCore::TextEvent::createForPlainTextPaste):
(WebCore::TextEvent::createForFragmentPaste):
(WebCore::TextEvent::createForDrop):
(WebCore::TextEvent::createForDictation):
* dom/TextEvent.h:
* dom/TouchEvent.h:
* dom/TransitionEvent.h:
* dom/UIEvent.h:
(WebCore::UIEvent::create):
* dom/WebKitAnimationEvent.h:
* dom/WebKitTransitionEvent.h:
* dom/WheelEvent.h:
* html/MediaKeyEvent.h:
* html/canvas/WebGLContextEvent.h:
* html/track/TrackEvent.h:
* storage/StorageEvent.cpp:
(WebCore::StorageEvent::create):
* storage/StorageEvent.h:
* svg/SVGZoomEvent.h:
(WebCore::SVGZoomEvent::create):
* xml/XMLHttpRequestProgressEvent.h:
(WebCore::XMLHttpRequestProgressEvent::create):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@177264 268f45cc-cd09-0410-ab3c-d52691b4dbfc