Fix android_webview FindBugs warnings revealed by N sdk

android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java

Index: android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
diff --git a/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java b/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
index a8a91e1d4846b7f76f02d40c62214c5f1c563d02..190ddea61ea991c5b7b36a05df87630fafcf07cf 100644
--- a/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
+++ b/android_webview/javatests/src/org/chromium/android_webview/test/VisualStateTest.java
@@ -20,6 +20,7 @@ import org.chromium.android_webview.test.util.CommonResources;
 import org.chromium.android_webview.test.util.GraphicsTestUtils;
 import org.chromium.android_webview.test.util.JavascriptEventObserver;
 import org.chromium.base.ThreadUtils;
+import org.chromium.base.annotations.SuppressFBWarnings;
 import org.chromium.base.test.util.Feature;
 import org.chromium.content.browser.ContentViewCore;
 import org.chromium.content.browser.test.util.CallbackHelper;
@@ -435,6 +436,7 @@ public class VisualStateTest extends AwTestBase {
 
         // JS will notify this observer once it has changed the background color of the page.
         final Object pageChangeNotifier = new Object() {
+            @SuppressFBWarnings("UMAC_UNCALLABLE_METHOD_OF_ANONYMOUS_CLASS")
             public void onPageChanged() {
                 ThreadUtils.postOnUiThread(new Runnable() {
                     @Override