webview js: Fold image URL rewriting into processIncomingHtml.

Also eliminate the legacy optionality of the second parameter.

This potentially involves some minor functional changes to
`handleInitialLoad`, in that the order of actions therewithin is
changed -- but if those actions don't commute, then we should
probably have been rewriting the source HTML before scrolling anyway.

src/webview/js/generatedEs3.js

@@ -18,8 +18,7 @@ var compiledWebviewJs = (function (exports) {
     return new RegExp(r);
   });
 
-  var rewriteImageUrls = function rewriteImageUrls(auth) {
-    var element = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : document;
+  var rewriteImageUrls = function rewriteImageUrls(auth, element) {
     var realm = new URL(auth.realm);
     var imageTags = [].concat(element instanceof HTMLImageElement ? [element] : [], Array.from(element.getElementsByTagName('img')));
     imageTags.forEach(function (img) {
@@ -396,14 +395,15 @@ var compiledWebviewJs = (function (exports) {
     window.scrollBy(0, newBoundRect.top - prevBoundTop);
   };
 
-  var processIncomingHtml = function processIncomingHtml(root) {
+  var processIncomingHtml = function processIncomingHtml(auth, root) {
+    rewriteImageUrls(auth, root);
     fixupKatex(root);
   };
 
   var handleUpdateEventContent = function handleUpdateEventContent(uevent) {
     var contentNode = document.createElement('div');
     contentNode.innerHTML = uevent.content;
-    processIncomingHtml(contentNode);
+    processIncomingHtml(uevent.auth, contentNode);
     var target;
 
     if (uevent.updateStrategy === 'replace') {
@@ -424,7 +424,6 @@ var compiledWebviewJs = (function (exports) {
     }
 
     documentBody.innerHTML = contentNode.innerHTML;
-    rewriteImageUrls(uevent.auth);
 
     if (target.type === 'bottom') {
       scrollToBottom();
@@ -444,11 +443,10 @@ var compiledWebviewJs = (function (exports) {
       document.addEventListener('message', handleMessageEvent);
     }
 
+    processIncomingHtml(auth, documentBody);
     scrollToMessage(scrollMessageId);
-    rewriteImageUrls(auth);
     sendScrollMessageIfListShort();
     scrollEventsDisabled = false;
-    processIncomingHtml(documentBody);
   };
 
   var handleUpdateEventFetching = function handleUpdateEventFetching(uevent) {

src/webview/js/js.js

@@ -481,15 +481,16 @@ const scrollToPreserve = (msgId: number, prevBoundTop: number) => {
  *
  * The root itself must not need fixups.
  */
-const processIncomingHtml = (root: Element) => {
+const processIncomingHtml = (auth: Auth, root: Element) => {
+  rewriteImageUrls(auth, root);
   fixupKatex(root);
 };
 
 const handleUpdateEventContent = (uevent: WebViewUpdateEventContent) => {
   // Perform preprocessing on the webview content.
   const contentNode: HTMLDivElement = document.createElement('div');
   contentNode.innerHTML = uevent.content;
-  processIncomingHtml(contentNode);
+  processIncomingHtml(uevent.auth, contentNode);
 
   let target: ScrollTarget;
   if (uevent.updateStrategy === 'replace') {
@@ -512,8 +513,6 @@ const handleUpdateEventContent = (uevent: WebViewUpdateEventContent) => {
   // (which currently breaks our touch event handling).
   documentBody.innerHTML = contentNode.innerHTML;
 
-  rewriteImageUrls(uevent.auth);
-
   if (target.type === 'bottom') {
     scrollToBottom();
   } else if (target.type === 'anchor') {
@@ -541,12 +540,10 @@ export const handleInitialLoad = (
     document.addEventListener('message', handleMessageEvent);
   }
 
+  processIncomingHtml(auth, documentBody);
   scrollToMessage(scrollMessageId);
-  rewriteImageUrls(auth);
   sendScrollMessageIfListShort();
   scrollEventsDisabled = false;
-
-  processIncomingHtml(documentBody);
 };
 
 /*

src/webview/js/rewriteImageUrls.js

@@ -14,11 +14,8 @@ const inlineApiRoutes: RegExp[] = ['^/user_uploads/', '^/thumbnail$', '^/avatar/
  *      than the document location.
  *   2. If the source URL names an endpoint known to require authentication,
  *      inject an API key into its query parameters.
- *
- * DEPRECATED: If no root element is specified, transform every <img> in the
- * entire document.
  */
-const rewriteImageUrls = (auth: Auth, element: Element | Document = document) => {
+const rewriteImageUrls = (auth: Auth, element: Element) => {
   const realm = new URL(auth.realm);
 
   // Find the image elements to act on.