Update the lower bound for UMA_HISTOGRAM_CUSTOM_COUNTS

The lower bound for UMA_HISTOGRAM_CUSTOM_COUNTS should be one or more.
https://cs.chromium.org/chromium/src/base/metrics/histogram.cc?rcl=0&l=376
Values of 0 or less is adjusted to 1 and a warning is written to the log.

BUG=
[email protected]
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2269553002
Cr-Commit-Position: refs/heads/master@{#413678}
diff --git a/components/variations/variations_http_header_provider.cc b/components/variations/variations_http_header_provider.cc
index 6337dc04..5af7151 100644
--- a/components/variations/variations_http_header_provider.cc
+++ b/components/variations/variations_http_header_provider.cc
@@ -186,7 +186,7 @@
 
   UMA_HISTOGRAM_CUSTOM_COUNTS(
       "Variations.HeaderConstructionTime",
-      (base::TimeTicks::Now() - before_time).InMicroseconds(), 0,
+      (base::TimeTicks::Now() - before_time).InMicroseconds(), 1,
       base::TimeDelta::FromSeconds(1).InMicroseconds(), 50);
 
   variation_ids_cache_initialized_ = true;