--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@@ -4987,17 +4987,17 @@ var CombinedStopReload = {
       this.animate = Services.prefs.getBoolPref("toolkit.cosmeticAnimations.enabled") &&
                      Services.prefs.getBoolPref("browser.stopReloadAnimation.enabled");
       Services.prefs.addObserver("toolkit.cosmeticAnimations.enabled", this);
       this.stopReloadContainer.addEventListener("animationend", this);
     });
   },
 
   switchToStop(aRequest, aWebProgress) {
-    if (!this._initialized || !this._shouldSwitch(aRequest))
+    if (!this._initialized)
       return;
 
     let shouldAnimate = AppConstants.MOZ_PHOTON_ANIMATIONS &&
                         aRequest instanceof Ci.nsIRequest &&
                         aWebProgress.isTopLevel &&
                         aWebProgress.isLoadingDocument &&
                         this.animate;
 
@@ -5005,18 +5005,17 @@ var CombinedStopReload = {
     if (shouldAnimate)
       this.stopReloadContainer.setAttribute("animate", "true");
     else
       this.stopReloadContainer.removeAttribute("animate");
     this.reload.setAttribute("displaystop", "true");
   },
 
   switchToReload(aRequest, aWebProgress) {
-    if (!this._initialized || !this._shouldSwitch(aRequest) ||
-        !this.reload.hasAttribute("displaystop"))
+    if (!this._initialized)
       return;
 
     let shouldAnimate = AppConstants.MOZ_PHOTON_ANIMATIONS &&
                         aRequest instanceof Ci.nsIRequest &&
                         aWebProgress.isTopLevel &&
                         !aWebProgress.isLoadingDocument &&
                         this.animate;
 
@@ -5043,29 +5042,16 @@ var CombinedStopReload = {
     this.reload.disabled = true;
     this._timer = setTimeout(function(self) {
       self._timer = 0;
       self.reload.disabled = XULBrowserWindow.reloadCommand
                                              .getAttribute("disabled") == "true";
     }, 650, this);
   },
 
-  _shouldSwitch(aRequest) {
-    if (!aRequest ||
-        !aRequest.originalURI ||
-        aRequest.originalURI.spec.startsWith("about:reader"))
-      return true;
-
-    if (aRequest.originalURI.schemeIs("chrome") ||
-        aRequest.originalURI.schemeIs("about"))
-      return false;
-
-    return true;
-  },
-
   _cancelTransition() {
     if (this._timer) {
       clearTimeout(this._timer);
       this._timer = 0;
     }
   }
 };
 

deleted file mode 100644
--- a/browser/base/content/test/about/.eslintrc.js
+++ /dev/null
@@ -1,7 +0,0 @@
-"use strict";
-
-module.exports = {
-  "extends": [
-    "plugin:mozilla/browser-test"
-  ]
-};

deleted file mode 100644
--- a/browser/base/content/test/about/browser.ini
+++ /dev/null
@@ -1,1 +0,0 @@
-[browser_aboutStopReload.js]

deleted file mode 100644
--- a/browser/base/content/test/about/browser_aboutStopReload.js
+++ /dev/null
@@ -1,90 +0,0 @@
-async function waitForNoAnimation(elt) {
-  return BrowserTestUtils.waitForCondition(() => !elt.hasAttribute("animate"));
-}
-
-async function getAnimatePromise(elt) {
-  return BrowserTestUtils.waitForAttribute("animate", elt)
-    .then(() => Assert.ok(true, `${elt.id} should animate`));
-}
-
-function stopReloadMutationCallback() {
-  Assert.ok(false, "stop-reload's animate attribute should not have been mutated");
-}
-
-add_task(async function checkDontShowStopOnNewTab() {
-  let stopReloadContainer = document.getElementById("stop-reload-button");
-  let stopReloadContainerObserver = new MutationObserver(stopReloadMutationCallback);
-
-  await waitForNoAnimation(stopReloadContainer);
-  stopReloadContainerObserver.observe(stopReloadContainer, { attributeFilter: ["animate"]});
-  let tab = await BrowserTestUtils.openNewForegroundTab({gBrowser,
-                                                        opening: "about:home",
-                                                        waitForStateStop: true});
-  await BrowserTestUtils.removeTab(tab);
-
-  Assert.ok(true, "Test finished: stop-reload does not animate when navigating to local URI on new tab");
-  stopReloadContainerObserver.disconnect();
-});
-
-add_task(async function checkDontShowStopFromLocalURI() {
-  let stopReloadContainer = document.getElementById("stop-reload-button");
-  let stopReloadContainerObserver = new MutationObserver(stopReloadMutationCallback);
-
-  let tab = await BrowserTestUtils.openNewForegroundTab({gBrowser,
-                                                        opening: "about:home",
-                                                        waitForStateStop: true});
-  await waitForNoAnimation(stopReloadContainer);
-  stopReloadContainerObserver.observe(stopReloadContainer, { attributeFilter: ["animate"]});
-  await BrowserTestUtils.loadURI(tab.linkedBrowser, "about:mozilla");
-  await BrowserTestUtils.removeTab(tab);
-
-  Assert.ok(true, "Test finished: stop-reload does not animate when navigating between local URIs");
-  stopReloadContainerObserver.disconnect();
-});
-
-add_task(async function checkDontShowStopFromNonLocalURI() {
-  let stopReloadContainer = document.getElementById("stop-reload-button");
-  let stopReloadContainerObserver = new MutationObserver(stopReloadMutationCallback);
-
-  let tab = await BrowserTestUtils.openNewForegroundTab({gBrowser,
-                                                        opening: "https://example.com",
-                                                        waitForStateStop: true});
-  await waitForNoAnimation(stopReloadContainer);
-  stopReloadContainerObserver.observe(stopReloadContainer, { attributeFilter: ["animate"]});
-  await BrowserTestUtils.loadURI(tab.linkedBrowser, "about:mozilla");
-  await BrowserTestUtils.removeTab(tab);
-
-  Assert.ok(true, "Test finished: stop-reload does not animate when navigating to local URI from non-local URI");
-  stopReloadContainerObserver.disconnect();
-});
-
-add_task(async function checkDoShowStopOnNewTab() {
-  let stopReloadContainer = document.getElementById("stop-reload-button");
-  let animatePromise = getAnimatePromise(stopReloadContainer);
-
-  await waitForNoAnimation(stopReloadContainer);
-  let tab = await BrowserTestUtils.openNewForegroundTab({gBrowser,
-                                                        opening: "https://example.com",
-                                                        waitForStateStop: true});
-  await animatePromise;
-  await waitForNoAnimation(stopReloadContainer);
-  await BrowserTestUtils.removeTab(tab);
-
-  info("Test finished: stop-reload animates when navigating to non-local URI on new tab");
-});
-
-add_task(async function checkDoShowStopFromLocalURI() {
-  let stopReloadContainer = document.getElementById("stop-reload-button");
-
-  await waitForNoAnimation(stopReloadContainer);
-  let tab = await BrowserTestUtils.openNewForegroundTab({gBrowser,
-                                                        opening: "about:home",
-                                                        waitForStateStop: true});
-  let animatePromise = getAnimatePromise(stopReloadContainer);
-  BrowserTestUtils.loadURI(tab.linkedBrowser, "https://example.com");
-  await animatePromise;
-  await waitForNoAnimation(stopReloadContainer);
-  await BrowserTestUtils.removeTab(tab);
-
-  info("Test finished: stop-reload animates when navigating local URI from non-local URI");
-});

--- a/browser/base/moz.build
+++ b/browser/base/moz.build
@@ -10,17 +10,16 @@ MOCHITEST_MANIFESTS += [
     'content/test/general/mochitest.ini',
 ]
 
 MOCHITEST_CHROME_MANIFESTS += [
     'content/test/chrome/chrome.ini',
 ]
 
 BROWSER_CHROME_MANIFESTS += [
-    'content/test/about/browser.ini',
     'content/test/alerts/browser.ini',
     'content/test/captivePortal/browser.ini',
     'content/test/contextMenu/browser.ini',
     'content/test/forms/browser.ini',
     'content/test/general/browser.ini',
     'content/test/newtab/browser.ini',
     'content/test/pageinfo/browser.ini',
     'content/test/performance/browser.ini',