remove voice button when unsupported

       http://b/issue?id=3338108
       voice search button is hidden if the selected search engine
       does not support voice search

Change-Id: I410d9e0a5fff7b0c045a3f0b1818fac03b247897
diff --git a/src/com/android/browser/TitleBarXLarge.java b/src/com/android/browser/TitleBarXLarge.java
index 57cc724..8be4df5 100644
--- a/src/com/android/browser/TitleBarXLarge.java
+++ b/src/com/android/browser/TitleBarXLarge.java
@@ -17,6 +17,7 @@
 package com.android.browser;
 
 import com.android.browser.UrlInputView.UrlInputListener;
+import com.android.browser.search.SearchEngine;
 
 import android.app.Activity;
 import android.app.SearchManager;
@@ -373,7 +374,11 @@
     }
 
     private void setSearchMode(boolean voiceSearchEnabled) {
-        mVoiceSearch.setVisibility(voiceSearchEnabled ? View.VISIBLE :
+        SearchEngine searchEngine = BrowserSettings.getInstance()
+                .getSearchEngine();
+        boolean showvoicebutton = voiceSearchEnabled &&
+                (searchEngine != null && searchEngine.supportsVoiceSearch());
+        mVoiceSearch.setVisibility(showvoicebutton ? View.VISIBLE :
                 View.GONE);
         mGoButton.setVisibility(voiceSearchEnabled ? View.GONE :
                 View.VISIBLE);