Remove temporary metric that violates I/O restrictions.

BUG=739941

Change-Id: I385237e7643707381109879908bf5d493bf62345
Reviewed-on: https://chromium-review.googlesource.com/563542
Commit-Queue: Brian White <bcwhite@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485137}

components/metrics/file_metrics_provider.cc

@@ -579,14 +579,6 @@ bool FileMetricsProvider::ProvideIndependentMetrics(
       UMA_HISTOGRAM_COUNTS_10000(
           "UMA.FileMetricsProvider.EmbeddedProfile.DroppedHistogramCount",
           histogram_count);
-
-      base::File::Info info;
-      if (base::GetFileInfo(source->path, &info)) {
-        UMA_HISTOGRAM_CUSTOM_COUNTS(
-            "UMA.FileMetricsProvider.EmbeddedProfile.DroppedFileAge",
-            (base::Time::Now() - info.last_modified).InMinutes(), 1,
-            base::TimeDelta::FromDays(30).InMinutes(), 50);
-      }
     }
 
     // Regardless of whether this source was successfully recorded, it is never

tools/metrics/histograms/histograms.xml

@@ -80492,6 +80492,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="UMA.FileMetricsProvider.EmbeddedProfile.DroppedFileAge"
     units="minutes">
+  <obsolete>
+    Deprecated 07/2017. Was only for short-term analysis. About 95% of dropped
+    files were less than 1 day old.
+  </obsolete>
   <owner>asvitkine@chromium.org</owner>
   <owner>bcwhite@chromium.org</owner>
   <summary>