HQPPerfTest: speed up test on dbg builds

Bug: 822624
Change-Id: I1ffee8e38bee2e016dc6beddd3eb05464def68a8
Reviewed-on: https://chromium-review.googlesource.com/966494
Commit-Queue: Charlie Harrison <csharrison@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#544812}

components/omnibox/browser/history_quick_provider_performance_unittest.cc

@@ -121,9 +121,17 @@ void HQPPerfTestOnePopularURL::TearDown() {
 }
 
 void HQPPerfTestOnePopularURL::PrepareData() {
-  // Adding fake urls to db must be done before RebuildFromHistory(). This will
-  // ensure that the index is properly populated with data from the database.
+// Adding fake urls to db must be done before RebuildFromHistory(). This will
+// ensure that the index is properly populated with data from the database.
+// Note: on debug builds these tests can be slow. Use a smaller data set in
+// that case. See crbug.com/822624.
+#if defined NDEBUG
   constexpr size_t kSimilarUrlCount = 10000;
+#else
+  LOG(ERROR) << "HQP performance test is running on a debug build, results may "
+                "not be accurate.";
+  constexpr size_t kSimilarUrlCount = 100;
+#endif
   for (size_t i = 0; i < kSimilarUrlCount; ++i)
     AddFakeURLToHistoryDB(history_backend()->db(), GeneratePopularURLRow());