Remove CertCacheTrial (DiskBasedCertCache).

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index d45ad8ebef07828c557d755f01240eda00ade392..088a92f7e35a00ce2a99f817e163d4a7acca63ad 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -7575,6 +7575,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="DiskBasedCertCache.CertIo" enum="CertificateChainPosition">
+  <obsolete>
+    Deprecated as of 01/2016. CertCacheTrial has been removed.
+    https://crbug.com/522312
+  </obsolete>
   <owner>brandonsalmon@chromium.org</owner>
   <summary>
     Records information about DiskBasedCertCache operations with respect to
@@ -7584,6 +7588,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="DiskBasedCertCache.CertIoCacheResult" enum="CacheResult">
+  <obsolete>
+    Deprecated as of 01/2016. CertCacheTrial has been removed.
+    https://crbug.com/522312
+  </obsolete>
   <owner>brandonsalmon@chromium.org</owner>
   <summary>
     Records the outcome of requests to retrieve certificates from the disk
@@ -7593,6 +7601,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="DiskBasedCertCache.CertIoReadSuccessLeaf"
     enum="BooleanSuccess">
+  <obsolete>
+    Deprecated as of 01/2016. CertCacheTrial has been removed.
+    https://crbug.com/522312
+  </obsolete>
   <owner>brandonsalmon@chromium.org</owner>
   <summary>
     Whether or not the leaf certificate of a certificate chain was successfuly
@@ -7602,6 +7614,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 
 <histogram name="DiskBasedCertCache.CertIoWriteSuccessLeaf"
     enum="BooleanSuccess">
+  <obsolete>
+    Deprecated as of 01/2016. CertCacheTrial has been removed.
+    https://crbug.com/522312
+  </obsolete>
   <owner>brandonsalmon@chromium.org</owner>
   <summary>
     Whether or not the leaf certificate of a certificate chain was successfully
@@ -7610,6 +7626,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="DiskBasedCertCache.ChainReadTime" units="ms">
+  <obsolete>
+    Deprecated as of 01/2016. CertCacheTrial has been removed.
+    https://crbug.com/522312
+  </obsolete>
   <owner>brandonsalmon@chromium.org</owner>
   <summary>
     Measures the wall clock time spent reading a certificate chain. The starting
@@ -7619,6 +7639,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </histogram>
 
 <histogram name="DiskBasedCertCache.ChainWriteTime" units="ms">
+  <obsolete>
+    Deprecated as of 01/2016. CertCacheTrial has been removed.
+    https://crbug.com/522312
+  </obsolete>
   <owner>brandonsalmon@chromium.org</owner>
   <summary>
     Measures the wall clock time spent writing a certificate chain to disk. The
@@ -58128,6 +58152,10 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
 </enum>
 
 <enum name="CertificateChainPosition" type="int">
+  <obsolete>
+    Deprecated as of 01/2016. CertCacheTrial has been removed.
+    https://crbug.com/522312
+  </obsolete>
   <int value="0" label="Root Certificate"/>
 </enum>
 
@@ -81273,6 +81301,10 @@ To add a new entry, add it with any value and run test to compute valid value.
 </histogram_suffixes>
 
 <histogram_suffixes name="CertIo" separator="">
+  <obsolete>
+    Deprecated as of 01/2016. CertCacheTrial has been removed.
+    https://crbug.com/522312
+  </obsolete>
   <suffix name="ReadSuccess"
       label="success rate of reading a certificate from the disk cache"/>
   <suffix name="ReadFailure"