[NTP Snippets] Make a base::Feature instead of raw cmdline flag

chrome/android/java/src/org/chromium/chrome/browser/ntp/NewTabPage.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.ntp;
 
 import android.annotation.TargetApi;
 import android.app.Activity;
 import android.app.ActivityManager;
 import android.app.Dialog;
@@ skipping 622 matching lines @@
     }
 
     private boolean isInSingleUrlBarMode(Context context) {
         if (mIsTablet) return false;
         if (mOptOutPromoShown) return false;
 
         return mSearchProviderHasLogo;
     }
 
     private void updateSearchProviderHasLogo() {
-        if (CommandLine.getInstance().hasSwitch(ChromeSwitches.ENABLE_NTP_SNIPPETS)) {
+        if (ChromeFeatureList.isEnabled("NTPSnippets")) {

[Bernhard Bauer, 2016/02/09 14:44:20]

It seems like this should also get extract to a string constant. Would it make
sense to move this to a class like ChromeFeatures?

[Marc Treib, 2016/02/10 11:18:40]

I've added a constant to the existing ChromeFeatureList class - that's what you
meant, right? (We *could* of course make a method to retrieve the actual string
from native instead of duplicating it, but that doesn't seem worth a
Java->native roundtrip - WDYT?)

[Bernhard Bauer, 2016/02/10 11:24:56]

Pretty much -- although I was more thinking of putting it into a separate class,
in the same way that CommandLine and ChromeSwitches are different classes. But
this is fine.
Yeah, I agree. If anything, we could look into automatically generating the Java
strings from the C++ strings, like we do for enums.

             mSearchProviderHasLogo = false;
             if (mNewTabPageView != null) mNewTabPageView.setSearchProviderHasLogo(false);
         } else {
             mSearchProviderHasLogo = !mOptOutPromoShown
                     && TemplateUrlService.getInstance().isDefaultSearchEngineGoogle();
         }
     }
 
     private void onSearchEngineUpdated() {
         // TODO(newt): update this if other search providers provide logos.
@@ skipping 156 matching lines @@
     @Override
     public boolean shouldCaptureThumbnail() {
         return mNewTabPageView.shouldCaptureThumbnail();
     }
 
     @Override
     public void captureThumbnail(Canvas canvas) {
         mNewTabPageView.captureThumbnail(canvas);
     }
 }