<https://webkit.org/b/127290>

Everyone who creates a RenderImage immediately follows up with
creating a RenderImageResource and assigning it to the image.

Let the RenderImage constructor do this instead, and make the
imageResource() accessors return references. This exposed a
number of unnecessary null checks.

Also modernized the touched code with std::unique_ptr.

Reviewed by Antti Koivisto.

* html/HTMLImageElement.cpp:
(WebCore::HTMLImageElement::createElementRenderer):
(WebCore::HTMLImageElement::didAttachRenderers):
* html/HTMLPlugInImageElement.cpp:
(WebCore::HTMLPlugInImageElement::createElementRenderer):
* html/HTMLVideoElement.cpp:
(WebCore::HTMLVideoElement::didAttachRenderers):
(WebCore::HTMLVideoElement::parseAttribute):
* html/ImageInputType.cpp:
(WebCore::ImageInputType::createInputRenderer):
(WebCore::ImageInputType::attach):
* loader/ImageLoader.cpp:
(WebCore::ImageLoader::renderImageResource):
* rendering/RenderElement.cpp:
(WebCore::RenderElement::createFor):
* rendering/RenderImage.cpp:
(WebCore::RenderImage::RenderImage):
(WebCore::RenderImage::~RenderImage):
(WebCore::RenderImage::styleDidChange):
(WebCore::RenderImage::imageChanged):
(WebCore::RenderImage::updateIntrinsicSizeIfNeeded):
(WebCore::RenderImage::updateInnerContentRect):
(WebCore::RenderImage::imageDimensionsChanged):
(WebCore::RenderImage::notifyFinished):
(WebCore::RenderImage::paintReplaced):
(WebCore::RenderImage::paintIntoRect):
(WebCore::RenderImage::foregroundIsKnownToBeOpaqueInRect):
(WebCore::RenderImage::minimumReplacedHeight):
(WebCore::RenderImage::computeIntrinsicRatioInformation):
(WebCore::RenderImage::embeddedContentBox):
* rendering/RenderImage.h:
(WebCore::RenderImage::imageResource):
(WebCore::RenderImage::cachedImage):
* rendering/RenderImageResource.h:
* rendering/RenderImageResourceStyleImage.h:
* rendering/RenderMedia.cpp:
(WebCore::RenderMedia::RenderMedia):
* rendering/RenderSnapshottedPlugIn.cpp:
(WebCore::RenderSnapshottedPlugIn::RenderSnapshottedPlugIn):
* rendering/RenderSnapshottedPlugIn.h:
* rendering/RenderVideo.cpp:
(WebCore::RenderVideo::calculateIntrinsicSize):
* rendering/style/ContentData.cpp:
(WebCore::ImageContentData::createContentRenderer):
* rendering/svg/RenderSVGImage.cpp:
(WebCore::RenderSVGImage::RenderSVGImage):
(WebCore::RenderSVGImage::~RenderSVGImage):
(WebCore::RenderSVGImage::updateImageViewport):
(WebCore::RenderSVGImage::paint):
(WebCore::RenderSVGImage::paintForeground):
* rendering/svg/RenderSVGImage.h:
* svg/SVGImageElement.cpp:
(WebCore::SVGImageElement::didAttachRenderers):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@162356 268f45cc-cd09-0410-ab3c-d52691b4dbfc