Remove @override to fix build break

Remove @override to fix a build break in master-gpl branch.

Change-Id: Id3f58dbecfec4a806f7857a6c1c73954e1bdd6e3
(cherry picked from commit 106c4320b02fb790d9955de133013662bbdc3094)
diff --git a/chromium/java/com/android/webview/chromium/WebViewChromiumFactoryProvider.java b/chromium/java/com/android/webview/chromium/WebViewChromiumFactoryProvider.java
index b823543..dccc855 100644
--- a/chromium/java/com/android/webview/chromium/WebViewChromiumFactoryProvider.java
+++ b/chromium/java/com/android/webview/chromium/WebViewChromiumFactoryProvider.java
@@ -274,7 +274,6 @@
                         }
                     }
 
-                    @Override
                     public void freeMemoryForTests() {
                         if (ActivityManager.isRunningInTestHarness()) {
                             MemoryPressureListener.maybeNotifyMemoryPresure(