Cherry-pick 5e8c33f. rdar://123409359

    Check both browser and chrome objects in enumerateFramesAndNamespaceObjects
    https://bugs.webkit.org/show_bug.cgi?id=270657
    rdar://123409359

    Reviewed by Timothy Hatcher.

    Some extensions use a polyfill to overwrite the browser object with their own proxy. The Blue Canoe extension was doing this,
    and it led to WebExtensionContextProxy::enumerateFramesAndNamespaceObjects not being able to find the namespace object for the extension,
    since we were only checking the `browser` object.

    To fix this, check both `browser` and `chrome`, and use whichever one is valid.

    * Source/WebKit/WebProcess/Extensions/WebExtensionContextProxy.cpp:
    (WebKit::WebExtensionContextProxy::enumerateFramesAndNamespaceObjects):

    Canonical link: https://commits.webkit.org/275809@main

Identifier: 273664.1362@safari-7619.1.5.6-branch

Source/WebKit/WebProcess/Extensions/WebExtensionContextProxy.cpp

@@ -184,11 +184,18 @@ void WebExtensionContextProxy::enumerateFramesAndNamespaceObjects(const Function
 
         auto context = page->isServiceWorkerPage() ? frame->jsContextForServiceWorkerWorld(world) : frame->jsContextForWorld(world);
         auto globalObject = JSContextGetGlobalObject(context);
-        auto namespaceObject = JSObjectGetProperty(context, globalObject, toJSString("browser").get(), nullptr);
-        if (!namespaceObject || !JSValueIsObject(context, namespaceObject))
-            continue;
 
-        RefPtr namespaceObjectImpl = toWebExtensionAPINamespace(context, namespaceObject);
+        RefPtr<WebExtensionAPINamespace> namespaceObjectImpl;
+        auto browserNamespaceObject = JSObjectGetProperty(context, globalObject, toJSString("browser").get(), nullptr);
+        if (browserNamespaceObject && JSValueIsObject(context, browserNamespaceObject))
+            namespaceObjectImpl = toWebExtensionAPINamespace(context, browserNamespaceObject);
+
+        if (!namespaceObjectImpl) {
+            auto chromeNamespaceObject = JSObjectGetProperty(context, globalObject, toJSString("chrome").get(), nullptr);
+            if (chromeNamespaceObject && JSValueIsObject(context, chromeNamespaceObject))
+                namespaceObjectImpl = toWebExtensionAPINamespace(context, chromeNamespaceObject);
+        }
+
         if (!namespaceObjectImpl)
             continue;