Enable import/export of passwords into/from Password Manager

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 82f8b6b664bd059e3a527d4ec1886c86ce9e2f84..39b639aa80aa2a7303b18b851996407b24809726 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -34076,6 +34076,21 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="PasswordManager.ExportedPasswordsPerUserInCSV">
+  <owner>xunlu@chromium.org</owner>
+  <owner>vabr@chromium.org</owner>
+  <summary>The number of passwords exported in CSV format per user.</summary>
+</histogram>
+
+<histogram name="PasswordManager.FailToStorePasswordImportedFromCSV">
+  <owner>xunlu@chromium.org</owner>
+  <owner>vabr@chromium.org</owner>
+  <summary>
+    The number of times password manager failed to store passwords imported from
+    a CSV file.
+  </summary>
+</histogram>
+
 <histogram name="PasswordManager.FilledCredentialWasFromAndroidApp"
     enum="PasswordManagerFilledAndroidCredentials">
   <owner>msramek@chromium.org</owner>
@@ -34117,6 +34132,22 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="PasswordManager.ImportedPasswordsPerUserInCSV">
+  <owner>xunlu@chromium.org</owner>
+  <owner>vabr@chromium.org</owner>
+  <summary>The number of passwords imported in CSV format per user</summary>
+</histogram>
+
+<histogram name="PasswordManager.ImportPasswordFromCSVResult"
+    enum="PasswordImportFromCSVResult">
+  <owner>xunlu@chromium.org</owner>
+  <owner>vabr@chromium.org</owner>
+  <summary>
+    The response code of successful or failed password import attempt from a CSV
+    file.
+  </summary>
+</histogram>
+
 <histogram name="PasswordManager.InfoBarResponse" enum="InfoBarResponse">
   <owner>vabr@chromium.org</owner>
   <summary>
@@ -76070,6 +76101,14 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="12" label="Generation triggered by autocomplete attributes"/>
 </enum>
 
+<enum name="PasswordImportFromCSVResult" type="int">
+  <int value="0" label="Password import succeeded"/>
+  <int value="1" label="Password import failed due to IO error"/>
+  <int value="2" label="Password import failed due to malformed CSV"/>
+  <int value="3" label="Password import failed due to missing content"/>
+  <int value="4" label="Boundary value"/>
+</enum>
+
 <enum name="PasswordManagerActionsTaken" type="int">
   <obsolete>
     Deprecated as of Chrome 32. See PasswordManagerActionsTakenWithPsl