Add UMA for Firefox passwords import

This CL add the following UMA:
1. If password is selected by user when importing Firefox profiles.
2. How many passwords are imported from Firefox.

R=isherman@chromium.org, vabr@chromium.org

Bug: 776664
Change-Id: Ife7b1079502d4c4f0ebd2fb473bceb5feec7ddbc
Reviewed-on: https://chromium-review.googlesource.com/744061
Commit-Queue: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Vaclav Brozek <vabr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#515407}

AUTHORS

@@ -892,6 +892,7 @@ Jan Rucka <ruckajan10@gmail.com>
 Yannic Bonenberger <contact@yannic-bonenberger.com>
 Kyoungdeok Kwon <kkd927@gmail.com>
 Kyungyoung Heo <bbvch13531@gmail.com>
+Jinyoung Hur <hurims@gmail.com>
 
 ACCESS CO., LTD. <*@access-company.com>
 BlackBerry Limited <*@blackberry.com>

chrome/utility/importer/firefox_importer.cc

@@ -13,6 +13,7 @@
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "build/build_config.h"
@@ -102,6 +103,9 @@ FirefoxImporter::~FirefoxImporter() {
 void FirefoxImporter::StartImport(const importer::SourceProfile& source_profile,
                                   uint16_t items,
                                   ImporterBridge* bridge) {
+  UMA_HISTOGRAM_BOOLEAN("Import.IncludesPasswords.Firefox",
+                        !!(items & importer::PASSWORDS));
+
   bridge_ = bridge;
   source_path_ = source_profile.source_path;
   app_path_ = source_profile.app_path;
@@ -374,6 +378,8 @@ void FirefoxImporter::ImportPasswords() {
   }
 
   if (!cancelled()) {
+    UMA_HISTOGRAM_COUNTS_10000("Import.NumberOfImportedPasswords.Firefox",
+                               forms.size());
     for (size_t i = 0; i < forms.size(); ++i) {
       if (!forms[i].username_value.empty() ||
           !forms[i].password_value.empty() ||

tools/metrics/histograms/histograms.xml

@@ -28274,6 +28274,28 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Import.IncludesPasswords.Firefox" enum="BooleanChecked">
+  <owner>vabr@chromium.org</owner>
+  <owner>hurims@gmail.com</owner>
+  <summary>
+    Whether or not the password checkbox is checked when importing a profile of
+    Firefox. Note that canceled imports could be counted also.
+  </summary>
+</histogram>
+
+<histogram name="Import.NumberOfImportedPasswords.Firefox">
+  <owner>vabr@chromium.org</owner>
+  <owner>hurims@gmail.com</owner>
+  <summary>
+    The number of passwords that are imported from Firefox. This is recorded
+    when importing a profile of Firefox with the password checkbox checked. Note
+    that the reported number of password could be slightly bigger than the
+    actual number of imported passwords because some incomplete or blacklisted
+    passwords that are dropped while importing might be included in the reported
+    value.
+  </summary>
+</histogram>
+
 <histogram name="Import.ShowDialog.FromBookmarkBarView" units="seconds">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>