diff --git a/chrome/browser/resources/chromeos/accessibility/common/local_storage_test.js b/chrome/browser/resources/chromeos/accessibility/common/local_storage_test.js
index f88b60f2..ddf234e 100644
--- a/chrome/browser/resources/chromeos/accessibility/common/local_storage_test.js
+++ b/chrome/browser/resources/chromeos/accessibility/common/local_storage_test.js
@@ -17,8 +17,15 @@
   }
 };
 
+// TODO(crbug.com/260589686): Remove after localStorage migration is done.
 AX_TEST_F(
     'AccessibilityExtensionLocalStorageTest', 'Migration', async function() {
+      if (isRunningInServiceWorker()) {
+        console.log(
+            'Skip because "localStorage" is not available in service worker.');
+        return;
+      }
+
       localStorage['catSound'] = 'meow';
       localStorage['catIsShy'] = String(false);
       localStorage['catIsFluffy'] = String(true);
diff --git a/chrome/browser/resources/chromeos/accessibility/common/testing/common.js b/chrome/browser/resources/chromeos/accessibility/common/testing/common.js
index 75c412d1..f5a0d6b 100644
--- a/chrome/browser/resources/chromeos/accessibility/common/testing/common.js
+++ b/chrome/browser/resources/chromeos/accessibility/common/testing/common.js
@@ -31,6 +31,19 @@
 }
 
 /**
+ * Helper to keep the service worker alive by calling an extension API.
+ * Caller should use `await` on the returned promise to yield control to
+ * allow the service worker to respond to pings.
+ */
+function keepServiceWorkerAlive() {
+  if (!isRunningInServiceWorker()) {
+    return Promise.resovle();
+  }
+
+  return chrome.runtime.getPlatformInfo();
+}
+
+/**
  * Helper to import a module, and expose it onto window.
  * @param {string|!Array<string>} toImport Names of the module exports to
  *     expose.
diff --git a/chrome/browser/resources/chromeos/accessibility/common/tree_walker_test.js b/chrome/browser/resources/chromeos/accessibility/common/tree_walker_test.js
index 74d081ab..470a69036 100644
--- a/chrome/browser/resources/chromeos/accessibility/common/tree_walker_test.js
+++ b/chrome/browser/resources/chromeos/accessibility/common/tree_walker_test.js
@@ -60,7 +60,7 @@
 TEST_F(
     'AccessibilityExtensionAutomationTreeWalkerTest', 'MAYBE_Forward',
     function() {
-      chrome.automation.getDesktop(this.newCallback(function(d) {
+      chrome.automation.getDesktop(this.newCallback(async function(d) {
         const resultList = [];
         this.flattenTree(d, resultList);
         let it = new AutomationTreeWalker(d, 'forward');
@@ -70,6 +70,10 @@
         assertEquals(null, it.next().node);
 
         for (let j = 0; j < resultList.length; j++) {
+          // This is needed because this iteration could take more than 30s on
+          // MSAN bots.
+          await keepServiceWorkerAlive();
+
           it = new AutomationTreeWalker(resultList[j], 'forward');
           const start = it.node;
           let cur = it.next().node;
@@ -91,7 +95,7 @@
 TEST_F(
     'AccessibilityExtensionAutomationTreeWalkerTest', 'MAYBE_Backward',
     function() {
-      chrome.automation.getDesktop(this.newCallback(function(d) {
+      chrome.automation.getDesktop(this.newCallback(async function(d) {
         const resultList = [];
         this.flattenTree(d, resultList);
         let it = new AutomationTreeWalker(
@@ -101,6 +105,10 @@
         }
 
         for (let j = resultList.length - 1; j >= 0; j--) {
+          // This is needed because this iteration could take more than 30s on
+          // MSAN bots.
+          await keepServiceWorkerAlive();
+
           it = new AutomationTreeWalker(resultList[j], 'backward');
           const start = it.node;
           let cur = it.next().node;
diff --git a/testing/variations/fieldtrial_testing_config.json b/testing/variations/fieldtrial_testing_config.json
index f84f5c5a..b81772f 100644
--- a/testing/variations/fieldtrial_testing_config.json
+++ b/testing/variations/fieldtrial_testing_config.json
@@ -180,6 +180,21 @@
             ]
         }
     ],
+    "AccessibilityManifestV3AccessibilityCommon": [
+        {
+            "platforms": [
+                "chromeos"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "AccessibilityManifestV3AccessibilityCommon"
+                    ]
+                }
+            ]
+        }
+    ],
     "AccessibilityManifestV3BrailleIme": [
         {
             "platforms": [