Merge 67734 - createBlobURL with no argument causes crash....

WebCore/dom/ScriptExecutionContext.cpp

Index: WebCore/dom/ScriptExecutionContext.cpp
===================================================================
--- WebCore/dom/ScriptExecutionContext.cpp	(revision 67741)
+++ WebCore/dom/ScriptExecutionContext.cpp	(working copy)
@@ -277,6 +277,8 @@
 #if ENABLE(BLOB)
 KURL ScriptExecutionContext::createPublicBlobURL(Blob* blob)
 {
+    if (!blob)
+        return KURL();
     KURL publicURL = BlobURL::createURL(this);
     ThreadableBlobRegistry::registerBlobURL(this, publicURL, blob->url());
     m_publicBlobURLs.add(publicURL.string());