Adding DiskBasedCertCache to HttpCache (+UMA).

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 e35ae92e0c9f08a2a52273a11e3c56362403f57b..5336d67f5c40528a2846d37171cb4c371402a2c0 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -3499,6 +3499,102 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="DiskBasedCertCache.ChainReadTime" units="milliseconds">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    Measures the wall time from when the writing of a certificate chain to disk
+    cache is issued until the last certificate is stored.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.ChainWriteTime" units="milliseconds">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    Measures the wall time from when the reading of a certificate chain to disk
+    cache is issued until the last certificate has been retrieved.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.ReadSuccessInt1">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the total number of successes versus failures in
+    reading the first intermediate x509 certificate from the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.ReadSuccessInt2">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the total number of successes versus failures in
+    reading the second intermediate x509 certificate from the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.ReadSuccessLeaf">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the total number of successes versus failures in
+    reading the leaf x509 certificate from the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.ReadSuccessRoot">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the number of successes versus failures in reading
+    root x509 certificates from the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.ReadSuccessTotal">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the total number of successes versus failures in
+    reading x509 certificates from the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.WriteSuccessInt1">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the total number of successes versus failures in
+    writing the first intermediate x509 certificate to the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.WriteSuccessInt2">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the total number of successes versus failures in
+    writing the second intermediate x509 certificate to the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.WriteSuccessLeaf">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the total number of successes versus failures in
+    writing the leaf x509 certificate to the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.WriteSuccessRoot">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the number of successes versus failures in writing
+    root x509 certificates to the disk cache.
+  </summary>
+</histogram>
+
+<histogram name="DiskBasedCertCache.WriteSuccessTotal">
+  <owner>brandonsalmon@chromium.org</owner>
+  <summary>
+    A boolean counter for the total number of successes versus failures in
+    writing x509 certificates to the disk cache.
+  </summary>
+</histogram>
+
 <histogram name="DiskCache.0.FilesAge" units="hours">
   <owner>rvargas@chromium.org</owner>
   <summary>The age of the cache's files (wall time).</summary>