Restrict transmission of external exp ids to signed in users.

components/omnibox/browser/zero_suggest_provider.cc

Index: components/omnibox/browser/zero_suggest_provider.cc
diff --git a/components/omnibox/browser/zero_suggest_provider.cc b/components/omnibox/browser/zero_suggest_provider.cc
index f848a3c8dd421015efcdb73258112d53bbcdebfc..652034f17f239585321703a38d3155ccac9ddf7c 100644
--- a/components/omnibox/browser/zero_suggest_provider.cc
+++ b/components/omnibox/browser/zero_suggest_provider.cc
@@ -333,9 +333,12 @@ void ZeroSuggestProvider::Run(const GURL& suggest_url) {
     fetcher_->SetLoadFlags(net::LOAD_DO_NOT_SAVE_COOKIES);
     // Add Chrome experiment state to the request headers.
     net::HttpRequestHeaders headers;
+    // Note: It's fine to pass in |is_signed_in| false, which does not affect
+    // transmission of experiment ids coming from the variations server.
+    bool is_signed_in = false;
     variations::AppendVariationHeaders(fetcher_->GetOriginalURL(),
                                        client()->IsOffTheRecord(), false,
-                                       &headers);
+                                       is_signed_in, &headers);
     fetcher_->SetExtraRequestHeaders(headers.ToString());
     fetcher_->Start();
     LogOmniboxZeroSuggestRequest(ZERO_SUGGEST_REQUEST_SENT);