Add UMA stats for chromeos dircrypto migration.

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 456522f7be5e0967c3375a3b69d9d8f180430f4d..c288dca57dabf774a7c26a8b21726f4710c525b8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -9462,6 +9462,24 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Cryptohome.DircryptoMigrationEndStatus"
+    enum="DircryptoMigrationStartStatus">
+  <owner>dspaid@chromium.org</owner>
+  <summary>
+    The status of the user home directory migration from ecryptfs to
+    ext4-crypto.  This is logged once at the end of each migration.
+  </summary>
+</histogram>
+
+<histogram name="Cryptohome.DircryptoMigrationStartStatus"
+    enum="DircryptoMigrationStartStatus">
+  <owner>dspaid@chromium.org</owner>
+  <summary>
+    The status of the user home directory migration from ecryptfs to
+    ext4-crypto.  This is logged once at the start of each migration.
+  </summary>
+</histogram>
+
 <histogram name="Cryptohome.Errors" enum="CryptohomeError">
   <owner>dkrahn@chromium.org</owner>
   <summary>Cryptohome errors.</summary>
@@ -9484,6 +9502,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Cryptohome.TimeToCompleteDircryptoMigration" units="ms">
+  <owner>dspaid@chromium.org</owner>
+  <summary>
+    The amount of time (ms) for the user's home directory to be migrated from
+    ecryptfs to ext4-crypto.  If the migration is interrupted and subsequently
+    resumed (such as due to power loss) the no value is recorded for either
+    attempt.
+  </summary>
+</histogram>
+
 <histogram name="Cryptohome.TimeToInitPkcs11" units="ms">
   <owner>dkrahn@chromium.org</owner>
   <summary>
@@ -89447,6 +89475,18 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="3" label="Primary accounts present but different"/>
 </enum>
 
+<enum name="DircryptoMigrationEndStatus" type="int">
+  <int value="1" label="New migration failed"/>
+  <int value="2" label="New migration succeeded"/>
+  <int value="3" label="Resumed migration failed"/>
+  <int value="4" label="Resumed migration succeeded"/>
+</enum>
+
+<enum name="DircryptoMigrationStartStatus" type="int">
+  <int value="1" label="Migration started"/>
+  <int value="2" label="Migration resumed"/>
+</enum>
+
 <enum name="DirectoryDatabaseRepairResult" type="int">
   <int value="0" label="Succeeded"/>
   <int value="1" label="Failed"/>