Implement Zen Welcome page with initial animation and styling; remove deprecated files

src/browser/base/content/browser-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/base/content/browser.js b/browser/base/content/browser.js
-index 019b168c1aeae7e1c97a3ae58c99a48a27f54134..1f051e8a1e8a58e8bb721196deecfa36f4089dd6 100644
+index 019b168c1aeae7e1c97a3ae58c99a48a27f54134..5225d0539aa7dabf81a8fd60af3e839f203d296c 100644
 --- a/browser/base/content/browser.js
 +++ b/browser/base/content/browser.js
 @@ -32,6 +32,7 @@ ChromeUtils.defineESModuleGetters(this, {
@@ -10,23 +10,7 @@ index 019b168c1aeae7e1c97a3ae58c99a48a27f54134..1f051e8a1e8a58e8bb721196deecfa36
    DevToolsSocketStatus:
      "resource://devtools/shared/security/DevToolsSocketStatus.sys.mjs",
    DownloadUtils: "resource://gre/modules/DownloadUtils.sys.mjs",
-@@ -632,6 +633,15 @@ XPCOMUtils.defineLazyPreferenceGetter(
-   false
- );
- 
-+const ZEN_WELCOME_PATH = "zen-welcome";
-+const ZEN_WELCOME_ELEMENT_ATTR = "zen-dialog-welcome-element";
-+XPCOMUtils.defineLazyServiceGetter(
-+  this,
-+  "ProfileService",
-+  "@mozilla.org/toolkit/profile-service;1",
-+  "nsIToolkitProfileService"
-+);
-+
- customElements.setElementCreationCallback("screenshots-buttons", () => {
-   Services.scriptloader.loadSubScript(
-     "chrome://browser/content/screenshots/screenshots-buttons.js",
-@@ -3440,6 +3450,10 @@ var XULBrowserWindow = {
+@@ -3440,6 +3441,10 @@ var XULBrowserWindow = {
      AboutReaderParent.updateReaderButton(gBrowser.selectedBrowser);
      TranslationsParent.onLocationChange(gBrowser.selectedBrowser);
  
@@ -37,7 +21,7 @@ index 019b168c1aeae7e1c97a3ae58c99a48a27f54134..1f051e8a1e8a58e8bb721196deecfa36
      PictureInPicture.updateUrlbarToggle(gBrowser.selectedBrowser);
  
      if (!gMultiProcessBrowser) {
-@@ -4435,7 +4449,7 @@ nsBrowserAccess.prototype = {
+@@ -4435,7 +4440,7 @@ nsBrowserAccess.prototype = {
      // Passing a null-URI to only create the content window,
      // and pass true for aSkipLoad to prevent loading of
      // about:blank
@@ -46,7 +30,7 @@ index 019b168c1aeae7e1c97a3ae58c99a48a27f54134..1f051e8a1e8a58e8bb721196deecfa36
        null,
        aParams,
        aWhere,
-@@ -4443,6 +4457,10 @@ nsBrowserAccess.prototype = {
+@@ -4443,6 +4448,10 @@ nsBrowserAccess.prototype = {
        aName,
        true
      );
@@ -57,16 +41,3 @@ index 019b168c1aeae7e1c97a3ae58c99a48a27f54134..1f051e8a1e8a58e8bb721196deecfa36
    },
  
    openURIInFrame: function browser_openURIInFrame(
-@@ -7285,6 +7303,12 @@ var gDialogBox = {
-     parentElement.showModal();
-     this._didOpenHTMLDialog = true;
- 
-+    if (uri.includes(ZEN_WELCOME_PATH)) {
-+      parentElement.setAttribute(ZEN_WELCOME_ELEMENT_ATTR, true);
-+    } else if (parentElement.hasAttribute(ZEN_WELCOME_ELEMENT_ATTR)) {
-+      parentElement.removeAttribute(ZEN_WELCOME_ELEMENT_ATTR);
-+    }
-+
-     // Disable menus and shortcuts.
-     this._updateMenuAndCommandState(false /* to disable */);
-