Bug 1877001 - Allow view-image to open a data: URI by setting a flag on the loadinfo. r=frg

suite/base/content/nsContextMenu.js

@@ -1086,6 +1086,7 @@ nsContextMenu.prototype = {
                        Ci.nsIScriptSecurityManager.DISALLOW_SCRIPT);
       openUILinkIn(this.mediaURL, where,
                    { referrerURI: doc.documentURIObject,
+                     forceAllowDataURI: true,
                      triggeringPrincipal: this.target.nodePrincipal,
                    });
     }

suite/base/content/utilityOverlay.js

@@ -1478,6 +1478,7 @@ function openLinkIn(url, where, params)
         params.referrerPolicy : Ci.nsIHttpChannel.REFERRER_POLICY_UNSET);
   var aRelatedToCurrent     = params.relatedToCurrent;
   var aAllowMixedContent    = params.allowMixedContent;
+  var aForceAllowDataURI    = params.forceAllowDataURI;
   var aInBackground         = params.inBackground;
   var aAvoidBrowserFocus    = params.avoidBrowserFocus;
   var aDisallowInheritPrincipal = params.disallowInheritPrincipal;
@@ -1607,6 +1608,9 @@ function openLinkIn(url, where, params)
     if (aDisallowInheritPrincipal) {
       flags |= Ci.nsIWebNavigation.LOAD_FLAGS_DISALLOW_INHERIT_OWNER;
     }
+    if (aForceAllowDataURI) {
+      flags |= Ci.nsIWebNavigation.LOAD_FLAGS_FORCE_ALLOW_DATA_URI;
+    }
 
     if (aForceAboutBlankViewerInCurrent) {
       w.gBrowser.selectedBrowser.createAboutBlankContentViewer(aPrincipal);