Fix rlz disabling breakage on CrOS

Revert of "Cache the brand code to avoid hundreds of repeated reads."
commit 04749717.
https://codereview.chromium.org/2890943005

Disabling RLZ is communicated through an empty brand code. Thus the
value of the brand code must not be cached before RLZ is initialized.

BUG=793162
TEST=none

Change-Id: I7f9e223a9a39d19408f364f6aad95cb8c86f6d79
Reviewed-on: https://chromium-review.googlesource.com/824363Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Thiemo Nagel <tnagel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524012}

chrome/browser/search_engines/ui_thread_search_terms_data.cc

@@ -68,15 +68,11 @@ base::string16 UIThreadSearchTermsData::GetRlzParameterValue(
       BrowserThread::CurrentlyOn(BrowserThread::UI));
   base::string16 rlz_string;
 #if BUILDFLAG(ENABLE_RLZ)
-  static std::string* brand = []() {
-    auto* extracted = new std::string();
-    if (!google_brand::GetBrand(extracted))
-      extracted->clear();
-    return extracted;
-  }();
   // For organic brandcodes do not use rlz at all. Empty brandcode usually
   // means a chromium install. This is ok.
-  if (!brand->empty() && !google_brand::IsOrganic(*brand)) {
+  std::string brand;
+  if (google_brand::GetBrand(&brand) && !brand.empty() &&
+      !google_brand::IsOrganic(brand)) {
     // This call will return false the first time(s) it is called until the
     // value has been cached. This normally would mean that at most one omnibox
     // search might not send the RLZ data but this is not really a problem.