<webview>: Fix missing transparency in captureVisibleRegion().

chrome/browser/extensions/api/tabs/tabs_api.cc

 // Copyright (c) 2012 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 "chrome/browser/extensions/api/tabs/tabs_api.h"
 
 #include <stddef.h>
 #include <algorithm>
 #include <limits>
 #include <utility>
@@ skipping 1649 matching lines @@
 
 bool TabsCaptureVisibleTabFunction::IsScreenshotEnabled() {
   PrefService* service = chrome_details_.GetProfile()->GetPrefs();
   if (service->GetBoolean(prefs::kDisableScreenshots)) {
     error_ = keys::kScreenshotsDisabled;
     return false;
   }
   return true;
 }
 
+bool TabsCaptureVisibleTabFunction::ClientAllowsTransparency() {
+  return false;
+}
+
 WebContents* TabsCaptureVisibleTabFunction::GetWebContentsForID(int window_id) {
   Browser* browser = NULL;
   if (!GetBrowserFromWindowID(&chrome_details_, window_id, &browser))
     return NULL;
 
   WebContents* contents = browser->tab_strip_model()->GetActiveWebContents();
   if (!contents) {
     error_ = "No active web contents to capture";
     return NULL;
   }
@@ skipping 456 matching lines @@
   ZoomModeToZoomSettings(zoom_mode, &zoom_settings);
   zoom_settings.default_zoom_factor.reset(new double(
       content::ZoomLevelToZoomFactor(zoom_controller->GetDefaultZoomLevel())));
 
   results_ = api::tabs::GetZoomSettings::Results::Create(zoom_settings);
   SendResponse(true);
   return true;
 }
 
 }  // namespace extensions