Deprecate Clients.getAll and introduce Clients.matchAll

Source/core/frame/UseCounter.cpp

Index: Source/core/frame/UseCounter.cpp
diff --git a/Source/core/frame/UseCounter.cpp b/Source/core/frame/UseCounter.cpp
index 90057450e6498f8373c85633f2249a792c341bb3..c7d01ec616a28ce69e55602bd32c1776ed2416f1 100644
--- a/Source/core/frame/UseCounter.cpp
+++ b/Source/core/frame/UseCounter.cpp
@@ -862,6 +862,9 @@ String UseCounter::deprecationMessage(Feature feature)
     case ServiceWorkerClientPostMessage:
         return "'Client.postMessage()' is an experimental API and may change. See https://github.com/slightlyoff/ServiceWorker/issues/609.";
 
+    case ServiceWorkerClientsGetAll:
+        return "'Clients.getAll()' is deprecated and will be removed soon. Please use 'Clients.matchAll()' instead.";
+
     // Features that aren't deprecated don't have a deprecation message.
     default:
         return String();