DCHECK for a valid error callback callback in GetIsPinnedToTaskbarState

chrome/browser/ui/webui/welcome_win10_handler.cc

 // Copyright 2016 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/ui/webui/welcome_win10_handler.h"
 
 #include "base/bind.h"
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/user_metrics.h"
 #include "base/strings/stringprintf.h"
@@ skipping 46 matching lines @@
   std::string histogram_suffix;
   histogram_suffix += inline_style_variant_ ? "Inline" : "Sectioned";
   histogram_suffix += pin_instructions_shown ? "Combined" : "Default";
 
   // Closing the page. Record whether the instructions were useful.
   (new shell_integration::DefaultBrowserWorker(
        base::Bind(&RecordDefaultBrowserResult, histogram_suffix)))
       ->StartCheckIsDefault();
 
   if (pin_instructions_shown) {
+    // On error, call RecordPinnedResult() with |succeeded| == false.
+    base::Closure error_callback =
+        base::Bind(&RecordPinnedResult, histogram_suffix, false, false);
     shell_integration::win::GetIsPinnedToTaskbarState(
-        base::Closure(), base::Bind(&RecordPinnedResult, histogram_suffix));
+        error_callback, base::Bind(&RecordPinnedResult, histogram_suffix));
   }
 }
 
 void WelcomeWin10Handler::RegisterMessages() {
   web_ui()->RegisterMessageCallback(
       "handleSetDefaultBrowser",
       base::Bind(&WelcomeWin10Handler::HandleSetDefaultBrowser,
                  base::Unretained(this)));
   web_ui()->RegisterMessageCallback(
       "handleContinue",
@@ skipping 82 matching lines @@
   // sent back.
   if (!pinned_state_callback_id_.empty())
     SendPinnedToTaskbarStateResult();
 }
 
 void WelcomeWin10Handler::SendPinnedToTaskbarStateResult() {
   ResolveJavascriptCallback(
       base::StringValue(pinned_state_callback_id_),
       base::FundamentalValue(pinned_state_result_.value()));
 }