Cherry-pick 1806344. rdar://121396693

    REGRESSION(273148@main): Crash on veggiegrill.com
    https://bugs.webkit.org/show_bug.cgi?id=267878

    Reviewed by Alex Christensen and Chris Dumez.

    There are some cases in which we enter this function with m_image being nullptr.
    Call updateFromElementIgnoringPreviousError in those cases.

    No new tests since I couldn't create a reliable reduction. The issue seems to be
    highly timing sensitive.

    * Source/WebCore/loader/ImageLoader.cpp:
    (WebCore::ImageLoader::updateFromElementIgnoringPreviousErrorToSameValue):

    Canonical link: https://commits.webkit.org/273321@main

Identifier: 273288.4@safari-7619.1.1-branch

Source/WebCore/loader/ImageLoader.cpp

@@ -341,7 +341,7 @@ void ImageLoader::updateFromElementIgnoringPreviousError(RelevantMutation releva
 
 void ImageLoader::updateFromElementIgnoringPreviousErrorToSameValue()
 {
-    if ((m_image && !m_image->allowsCaching()) || !m_failedLoadURL.isEmpty() || element().document().activeServiceWorker()) {
+    if (!m_image || !m_image->allowsCaching() || !m_failedLoadURL.isEmpty() || element().document().activeServiceWorker()) {
         updateFromElementIgnoringPreviousError(RelevantMutation::Yes);
         return;
     }