weblayer: Use static inner class where appropriate

Change-Id: I95df3ea154bb0a73b8842bd485129c4269d1eff0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879707Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709139}

weblayer/public/java/org/chromium/weblayer/BrowserController.java

@@ -152,7 +152,7 @@ public final class BrowserController {
         }
     }
 
-    private final class DownloadDelegateClientImpl extends IDownloadDelegateClient.Stub {
+    private static final class DownloadDelegateClientImpl extends IDownloadDelegateClient.Stub {
         private final DownloadDelegate mDelegate;
 
         DownloadDelegateClientImpl(DownloadDelegate delegate) {
@@ -171,7 +171,7 @@ public final class BrowserController {
         }
     }
 
-    private final class FullscreenDelegateClientImpl extends IFullscreenDelegateClient.Stub {
+    private static final class FullscreenDelegateClientImpl extends IFullscreenDelegateClient.Stub {
         private FullscreenDelegate mDelegate;
 
         /* package */ FullscreenDelegateClientImpl(FullscreenDelegate delegate) {