//components/google: use flat_set to hold static sets of strings.

It's more memory efficient than std::set. Also changes the sets to hold
StringPiece instead of std::string, since the sets only hold string
constants.

Change-Id: Ia5e8823e7285863724bb4a1956afaff2bc6186ea
Reviewed-on: https://chromium-review.googlesource.com/c/1298359Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602466}

components/google/core/common/google_util.cc

@@ -6,11 +6,11 @@
 
 #include <stddef.h>
 
-#include <set>
 #include <string>
 #include <vector>
 
 #include "base/command_line.h"
+#include "base/containers/flat_set.h"
 #include "base/macros.h"
 #include "base/no_destructor.h"
 #include "base/stl_util.h"
@@ -116,9 +116,9 @@ bool IsCanonicalHostGoogleHostname(base::StringPiece canonical_host,
   // same page.
   StripTrailingDot(&tld);
 
-  static base::NoDestructor<std::set<std::string>> google_tlds(
-      std::initializer_list<std::string>({GOOGLE_TLD_LIST}));
-  return base::ContainsKey(*google_tlds, tld.as_string());
+  static const base::NoDestructor<base::flat_set<base::StringPiece>>
+      google_tlds(std::initializer_list<base::StringPiece>({GOOGLE_TLD_LIST}));
+  return google_tlds->contains(tld);
 }
 
 // True if |url| is a valid URL with a host that is in the static list of
@@ -131,11 +131,11 @@ bool IsGoogleSearchSubdomainUrl(const GURL& url) {
   base::StringPiece host(url.host_piece());
   StripTrailingDot(&host);
 
-  static base::NoDestructor<std::set<std::string>> google_subdomains(
-      std::initializer_list<std::string>(
+  static const base::NoDestructor<base::flat_set<base::StringPiece>>
+      google_subdomains(std::initializer_list<base::StringPiece>(
           {"ipv4.google.com", "ipv6.google.com"}));
 
-  return base::ContainsKey(*google_subdomains, host.as_string());
+  return google_subdomains->contains(host);
 }
 
 }  // namespace