Rename infobar_close_button to btn_close.

chrome/android/java/res/layout/app_banner_view.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2014 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.
 -->
 
 <org.chromium.chrome.browser.banners.AppBannerView
         xmlns:android="http://schemas.android.com/apk/res/android"
         android:id="@+id/app_banner_view"
         android:background="@drawable/card_background_default"
@@ skipping 57 matching lines @@
                 android:id="@+id/app_rating"
                 android:adjustViewBounds="true"
                 android:layout_width="wrap_content"
                 android:layout_height="@dimen/app_banner_star_height" />
     
         <!-- Button that closes the banner. -->
         <ImageButton
                 android:id="@+id/close_button"
                 android:contentDescription="@string/infobar_close"
                 android:adjustViewBounds="true"
-                android:src="@drawable/infobar_close_button"
+                android:src="@drawable/btn_close"
                 android:background="@drawable/app_banner_button_close"
                 android:padding="@dimen/app_banner_close_button_padding"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"/>
     
         <!-- View covering the entire banner.  Used to indicate the banner is highlighted. -->
         <View
                 android:id="@+id/banner_highlight"
                 android:background="@color/app_banner_card_highlight"
                 android:visibility="gone"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent" />
     </FrameLayout>
 </org.chromium.chrome.browser.banners.AppBannerView>