AW: remove unnecessary annotations

No change to behavior.

This removes no-longer-needed annotations for Safe Browsing methods. For
initSafeBrowsing(), the SuppressWarnings and TargetApi annotations are
leftover from when this method relied on reflection. For other,
maybeEnableSafeBrowsingFromManifest, the SuppressWarnings annotation was
similarly leftover from reflection.

Bug: 682070
Test: N/A
Change-Id: I828dc570217742c4d052e3fb5ef16c799d7c9715
Reviewed-on: https://chromium-review.googlesource.com/991162Reviewed-by: Bo <boliu@chromium.org>
Commit-Queue: Nate Fischer <ntfschr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547739}

android_webview/java/src/org/chromium/android_webview/AwContentsStatics.java

@@ -4,7 +4,6 @@
 
 package org.chromium.android_webview;
 
-import android.annotation.TargetApi;
 import android.content.Context;
 import android.net.Uri;
 
@@ -109,8 +108,6 @@ public class AwContentsStatics {
         nativeSetSafeBrowsingWhitelist(urlArray, callback);
     }
 
-    @SuppressWarnings("unchecked")
-    @TargetApi(19)
     public static void initSafeBrowsing(Context context, final Callback<Boolean> callback) {
         // Wrap the callback to make sure we always invoke it on the UI thread, as guaranteed by the
         // API.

android_webview/java/src/org/chromium/android_webview/AwSafeBrowsingConfigHelper.java

@@ -44,7 +44,6 @@ public class AwSafeBrowsingConfigHelper {
                 "SafeBrowsing.WebView.AppOptIn", value, AppOptIn.COUNT);
     }
 
-    @SuppressWarnings("unchecked")
     public static void maybeEnableSafeBrowsingFromManifest(final Context appContext) {
         Boolean appOptIn = getAppOptInPreference(appContext);
         if (appOptIn == null) {