Reland "Cache brand code on Windows."

This reverts commit b93f6ee5.

Reason for revert: Reverting showed the relevant metrics regressed, so this change did have the expected improvement.

Original change's description:
> Revert "Cache brand code on Windows."
> 
> This reverts commit 9dd1ef42.
> 
> Reason for revert: Latest canary data did not have expected recovery on Omnibox.CharTypedToRepaintLatency and had a regression on Omnibox.CharTypedToRepaintLatency.ToPaint. Reverting to see if that movement is related to this CL or whether there were other changes in the meanwhile.
> 
> Original change's description:
> > Cache brand code on Windows.
> > 
> > Querying the registry is expensive and contributes to start up time,
> > omnibox query time and idle. Since the brand code is not expected to
> > change on Windows during the course of a session, this CL caches
> > the value, so that future queries are free.
> > 
> > This should restore the Omnibox perf that regressed by
> > https://chromium-review.googlesource.com/c/chromium/src/+/824363
> > and also improve perf elsewhere since the caching is now done at
> > a lower level than that change. Since this is expensive only on
> > Windows, the caching is done in the Windows codepath only.
> > 
> > Bug: 816698, 806130
> > Change-Id: I458fad29f18b1b1ff2d55b9334ae733fa448eec9
> > Reviewed-on: https://chromium-review.googlesource.com/947522
> > Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
> > Reviewed-by: Peter Kasting <pkasting@chromium.org>
> > Reviewed-by: Greg Thompson <grt@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#541009}
> 
> TBR=pkasting@chromium.org,asvitkine@chromium.org,grt@chromium.org
> 
> # Not skipping CQ checks because original CL landed > 1 day ago.
> 
> Bug: 816698, 806130
> Change-Id: I09e12c17011f72f25ecb369ca3075e2067013f8a
> Reviewed-on: https://chromium-review.googlesource.com/958012
> Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
> Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#542506}

TBR=pkasting@chromium.org,asvitkine@chromium.org,grt@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 816698, 806130
Change-Id: Id70bcaa6be1e91240010e74990dd2bd81d673258
Reviewed-on: https://chromium-review.googlesource.com/973581Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#544723}

chrome/browser/google/google_brand.cc

@@ -8,6 +8,8 @@
 #include <string>
 
 #include "base/macros.h"
+#include "base/no_destructor.h"
+#include "base/optional.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
@@ -41,11 +43,20 @@ bool GetBrand(std::string* brand) {
     return true;
   }
 
-  base::string16 brand16;
-  bool ret = GoogleUpdateSettings::GetBrand(&brand16);
-  if (ret)
-    brand->assign(base::UTF16ToASCII(brand16));
-  return ret;
+  // Cache brand code value, since it is queried a lot and registry queries are
+  // slow enough to actually affect top-level metrics like
+  // Omnibox.CharTypedToRepaintLatency.
+  static const base::NoDestructor<base::Optional<std::string>> brand_code(
+      []() -> base::Optional<std::string> {
+        base::string16 brand16;
+        if (!GoogleUpdateSettings::GetBrand(&brand16))
+          return base::nullopt;
+        return base::UTF16ToASCII(brand16);
+      }());
+  if (!brand_code->has_value())
+    return false;
+  brand->assign(**brand_code);
+  return true;
 }
 
 bool GetReactivationBrand(std::string* brand) {

chrome/browser/google/google_brand.h

@@ -18,6 +18,7 @@ namespace google_brand {
 
 // Returns in |brand| the brand code or distribution tag that has been
 // assigned to a partner. Returns false if the information is not available.
+// TODO(asvitkine): These APIs should return base::Optional<std::string>.
 bool GetBrand(std::string* brand);
 
 // Returns in |brand| the reactivation brand code or distribution tag