Remove PrintJobsQueued metric

ChromeOS printing team has enough data.  It's pretty much
always 1.

Bug: 1089320
Change-Id: I9683a47aed3f183d401ffe56ec21a7bb965abbcc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2447229
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814307}

chrome/browser/chromeos/printing/cups_print_job_manager_impl.cc

@@ -282,12 +282,6 @@ class CupsPrintJobManagerImpl : public CupsPrintJobManager,
       return false;
     }
 
-    // Records the number of jobs we're currently tracking when a new job is
-    // started.  This is equivalent to print queue size in the current
-    // implementation.
-    UMA_HISTOGRAM_EXACT_LINEAR("Printing.CUPS.PrintJobsQueued", jobs_.size(),
-                               20);
-
     // Create a new print job.
     auto cpj = std::make_unique<CupsPrintJob>(*printer, job_id, title,
                                               total_page_number, source,

tools/metrics/histograms/histograms_xml/printing/histograms.xml

@@ -281,6 +281,9 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 
 <histogram name="Printing.CUPS.PrintJobsQueued" units="count"
     expires_after="M85">
+  <obsolete>
+    New data not needed 2020-10
+  </obsolete>
   <owner>skau@chromium.org</owner>
   <summary>
     The size of the print queue when a print job is initially queued. When the