[Extensions] Remove UpdateCheckInfo constructor.

The conditional check for a null pointer value for g_test_clock
is unnecessary, since the constructor of net::BackoffEntry will
initialize the value to a nullptr anyway. This allowed removing
the constructor completely.

Change-Id: I02d62a79aba3257f50a0d5aae91d54ec9a612e9e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2430449Reviewed-by: Kelvin Jiang <kelvinjiang@chromium.org>
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811502}

chrome/browser/extensions/api/runtime/chrome_runtime_api_delegate.cc

@@ -122,16 +122,8 @@ const base::TickClock* g_test_clock = nullptr;
 }  // namespace
 
 struct ChromeRuntimeAPIDelegate::UpdateCheckInfo {
- public:
-  UpdateCheckInfo() {
-    if (g_test_clock)
-      backoff.reset(
-          new net::BackoffEntry(BackoffPolicy::Get(), g_test_clock));
-    else
-      backoff.reset(new net::BackoffEntry(BackoffPolicy::Get()));
-  }
-
-  std::unique_ptr<net::BackoffEntry> backoff;
+  std::unique_ptr<net::BackoffEntry> backoff =
+      std::make_unique<net::BackoffEntry>(BackoffPolicy::Get(), g_test_clock);
   std::vector<UpdateCheckCallback> callbacks;
 };