[Android WebView] Add an API to control favicon loading.

android_webview/browser/icon_helper.cc

 // Copyright (c) 2013 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.
 
 #include "android_webview/browser/icon_helper.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/logging.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 42 matching lines @@
 void IconHelper::DidUpdateFaviconURL(int32 page_id,
     const std::vector<content::FaviconURL>& candidates) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   for (std::vector<content::FaviconURL>::const_iterator i = candidates.begin();
        i != candidates.end(); ++i) {
     if (!i->icon_url.is_valid())
       continue;
 
     switch(i->icon_type) {
       case content::FaviconURL::FAVICON:
-        // TODO(acleung): only fetch the URL if favicon downloading is enabled.
-        // (currently that is, the app has called WebIconDatabase.open()
-        // but we should decouple that setting via a boolean setting)
+        if (listener_ && !listener_->ShouldDownloadFavicon(i->icon_url)) break;
         web_contents()->DownloadImage(i->icon_url,
             true,  // Is a favicon
             0,  // No maximum size
             base::Bind(
                 &IconHelper::DownloadFaviconCallback, base::Unretained(this)));
         break;
       case content::FaviconURL::TOUCH_ICON:
         if (listener_)
           listener_->OnReceivedTouchIconUrl(i->icon_url.spec(), false);
         break;
       case content::FaviconURL::TOUCH_PRECOMPOSED_ICON:
         if (listener_)
           listener_->OnReceivedTouchIconUrl(i->icon_url.spec(), true);
         break;
       case content::FaviconURL::INVALID_ICON:
         // Silently ignore it. Only trigger a callback on valid icons.
         break;
       default:
         NOTREACHED();
         break;
     }
   }
 }
 
 }  // namespace android_webview