Refactoring: Extracted SpellCheckHostMetrics class.

This is a preparaiton for making a part of spellcheck related metrics
out of SpellCheckHost lifetime. This change is just a refactoring
and should have no behavioral change.

BUG=none
TEST=manual


Review URL: http://codereview.chromium.org/7242007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@90341 0039d316-1c4b-4281-b951-d872f2087c98

11 files changed, 219 insertions, 182 deletions

diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index 6b92e21..73adc7f 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -64,6 +64,7 @@
 #include "chrome/browser/search_engines/template_url_service.h"
 #include "chrome/browser/sessions/session_service_factory.h"
 #include "chrome/browser/spellcheck_host.h"
+#include "chrome/browser/spellcheck_host_metrics.h"
 #include "chrome/browser/sync/profile_sync_factory_impl.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/tabs/pinned_tab_service_factory.h"
@@ -396,11 +397,13 @@ void ProfileImpl::DoFinalInit() {
 
   InstantController::RecordMetrics(this);
 
-  // Logs the spell-check enabled status.
-  // For simplicity, we check if spell-check is enabled only at start up
-  // time and don't track preferences change.
-  SpellCheckHost::RecordEnabledStats(
-      GetPrefs()->GetBoolean(prefs::kEnableSpellCheck));
+  // Instantiates Metrics object for spellchecking for use.
+  if (g_browser_process->metrics_service() &&
+      g_browser_process->metrics_service()->recording_active()) {
+    spellcheck_host_metrics_.reset(new SpellCheckHostMetrics());
+    spellcheck_host_metrics_->RecordEnabledStats(
+        GetPrefs()->GetBoolean(prefs::kEnableSpellCheck));
+  }
 
   FilePath cookie_path = GetPath();
   cookie_path = cookie_path.Append(chrome::kCookieFilename);
@@ -1267,7 +1270,7 @@ void ProfileImpl::ReinitializeSpellCheckHost(bool force) {
         this,
         prefs->GetString(prefs::kSpellCheckDictionary),
         GetRequestContext(),
-        g_browser_process->metrics_service()->recording_active());
+        spellcheck_host_metrics_.get());
   } else if (notify) {
     // The spellchecker has been disabled.
     SpellCheckHostInitialized();
diff --git a/chrome/browser/profiles/profile_impl.h b/chrome/browser/profiles/profile_impl.h
index 84dceec..014834f 100644
--- a/chrome/browser/profiles/profile_impl.h
+++ b/chrome/browser/profiles/profile_impl.h
@@ -22,6 +22,7 @@
 class ExtensionPrefs;
 class ExtensionPrefValueMap;
 class PrefService;
+class SpellCheckHostMetrics;
 
 #if defined(OS_CHROMEOS)
 namespace chromeos {
@@ -259,6 +260,7 @@ class ProfileImpl : public Profile,
   base::Time start_time_;
 
   scoped_refptr<SpellCheckHost> spellcheck_host_;
+  scoped_ptr<SpellCheckHostMetrics> spellcheck_host_metrics_;
 
   // Indicates whether |spellcheck_host_| has told us initialization is
   // finished.
diff --git a/chrome/browser/spellcheck_host.cc b/chrome/browser/spellcheck_host.cc
index 16e94b5..7ad4bb0 100644
--- a/chrome/browser/spellcheck_host.cc
+++ b/chrome/browser/spellcheck_host.cc
@@ -4,7 +4,6 @@
 
 #include "chrome/browser/spellcheck_host.h"
 
-#include "base/metrics/histogram.h"
 #include "base/string_split.h"
 #include "chrome/browser/prefs/pref_member.h"
 #include "chrome/browser/profiles/profile.h"
@@ -18,12 +17,12 @@ scoped_refptr<SpellCheckHost> SpellCheckHost::Create(
     SpellCheckHostObserver* observer,
     const std::string& language,
     net::URLRequestContextGetter* request_context_getter,
-    bool metrics_enabled) {
+    SpellCheckHostMetrics* metrics) {
   scoped_refptr<SpellCheckHostImpl> host =
       new SpellCheckHostImpl(observer,
                              language,
                              request_context_getter,
-                             metrics_enabled);
+                             metrics);
   if (!host)
     return NULL;
 
@@ -72,18 +71,3 @@ int SpellCheckHost::GetSpellCheckLanguages(
   }
   return -1;
 }
-
-// static
-void SpellCheckHost::RecordCustomWordCountStats(size_t count) {
-  UMA_HISTOGRAM_COUNTS("SpellCheck.CustomWords", count);
-}
-
-// static
-void SpellCheckHost::RecordEnabledStats(bool enabled) {
-  UMA_HISTOGRAM_BOOLEAN("SpellCheck.Enabled", enabled);
-  // Because SpellCheckHost is instantiated lazily, the size of
-  // custom dictionary is unknown at this time. We mark it as -1 and
-  // record actual value later. See SpellCheckHost for more detail.
-  if (enabled)
-    RecordCustomWordCountStats(-1);
-}
diff --git a/chrome/browser/spellcheck_host.h b/chrome/browser/spellcheck_host.h
index a174358..1d00e063 100644
--- a/chrome/browser/spellcheck_host.h
+++ b/chrome/browser/spellcheck_host.h
@@ -15,6 +15,7 @@
 
 class Profile;
 class RenderProcessHost;
+class SpellCheckHostMetrics;
 class SpellCheckHostObserver;
 
 namespace net {
@@ -53,15 +54,7 @@ class SpellCheckHost
       SpellCheckHostObserver* observer,
       const std::string& language,
       net::URLRequestContextGetter* request_context_getter,
-      bool metrics_enabled);
-
-  // Collects the number of words in the custom dictionary, which is
-  // to be uploaded via UMA
-  static void RecordCustomWordCountStats(size_t count);
-
-  // Collects status of spellchecking enabling state, which is
-  // to be uploaded via UMA
-  static void RecordEnabledStats(bool enabled);
+      SpellCheckHostMetrics* metrics);
 
   // Clears an observer which is set on creation.
   // Used to prevent calling back to a deleted object.
@@ -85,21 +78,9 @@ class SpellCheckHost
 
   virtual bool IsUsingPlatformChecker() const = 0;
 
-  // Collects status of spellchecking enabling state, which is
-  // to be uploaded via UMA
-  virtual void RecordCheckedWordStats(const string16& word, bool misspell) = 0;
-
-  // Collects a histogram for context menu showing as a spell correction
-  // attempt to be uploaded via UMA.
-  // The value of |delta| is accumulated to the total count, and only
-  // update tracked ratio if |delta| is zero.
-  virtual void RecordSuggestionStats(int delta) = 0;
-
-  // Collects a histogram for misspelled word replacement
-  // to be uploaded via UMA.
-  // The value of |delta| is accumulated to the total count, and only
-  // update tracked ratio if |delta| is zero.
-  virtual void RecordReplacedWordStats(int delta) = 0;
+  // Returns a metrics counter associated with this object,
+  // or null when metrics recording is disabled.
+  virtual SpellCheckHostMetrics* GetMetrics() const = 0;
 
   // This function computes a vector of strings which are to be displayed in
   // the context menu over a text area for changing spell check languages. It
diff --git a/chrome/browser/spellcheck_host_impl.cc b/chrome/browser/spellcheck_host_impl.cc
index 53621b6..f69c11d 100644
--- a/chrome/browser/spellcheck_host_impl.cc
+++ b/chrome/browser/spellcheck_host_impl.cc
@@ -8,14 +8,13 @@
 
 #include "base/file_util.h"
 #include "base/logging.h"
-#include "base/md5.h"
-#include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/string_split.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/spellcheck_host_metrics.h"
 #include "chrome/browser/spellcheck_host_observer.h"
 #include "chrome/browser/spellchecker_platform_engine.h"
 #include "chrome/common/chrome_constants.h"
@@ -84,19 +83,14 @@ SpellCheckHostImpl::SpellCheckHostImpl(
     SpellCheckHostObserver* observer,
     const std::string& language,
     net::URLRequestContextGetter* request_context_getter,
-    bool metrics_enabled)
+    SpellCheckHostMetrics* metrics)
     : observer_(observer),
       language_(language),
       file_(base::kInvalidPlatformFileValue),
       tried_to_download_(false),
       use_platform_spellchecker_(false),
       request_context_getter_(request_context_getter),
-      metrics_enabled_(metrics_enabled),
-      misspelled_word_count_(0),
-      spellchecked_word_count_(0),
-      suggestion_show_count_(0),
-      replaced_word_count_(0),
-      start_time_(base::Time::Now()) {
+      metrics_(metrics) {
   DCHECK(observer_);
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
@@ -107,12 +101,6 @@ SpellCheckHostImpl::SpellCheckHostImpl(
 
   registrar_.Add(this, NotificationType::RENDERER_PROCESS_CREATED,
                  NotificationService::AllSources());
-  if (metrics_enabled) {
-    const uint64 kHistogramTimerDurationInMinutes = 30;
-    histogram_timer_.Start(
-        base::TimeDelta::FromMinutes(kHistogramTimerDurationInMinutes),
-        this, &SpellCheckHostImpl::OnHistogramTimerExpired);
-  }
 }
 
 SpellCheckHostImpl::~SpellCheckHostImpl() {
@@ -183,7 +171,8 @@ void SpellCheckHostImpl::AddWord(const std::string& word) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   custom_words_.push_back(word);
-  SpellCheckHost::RecordCustomWordCountStats(custom_words_.size());
+  if (metrics_)
+    metrics_->RecordCustomWordCountStats(custom_words_.size());
   BrowserThread::PostTask(BrowserThread::FILE, FROM_HERE,
       NewRunnableMethod(this,
           &SpellCheckHostImpl::WriteWordToCustomDictionary, word));
@@ -251,7 +240,8 @@ void SpellCheckHostImpl::InitializeInternal() {
   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
       NewRunnableMethod(this,
           &SpellCheckHostImpl::InformObserverOfInitialization));
-  SpellCheckHost::RecordCustomWordCountStats(custom_words_.size());
+  if (metrics_)
+    metrics_->RecordCustomWordCountStats(custom_words_.size());
 }
 
 void SpellCheckHostImpl::InitializeOnFileThread() {
@@ -311,76 +301,6 @@ void SpellCheckHostImpl::WriteWordToCustomDictionary(const std::string& word) {
   file_util::CloseFile(f);
 }
 
-void SpellCheckHostImpl::RecordCheckedWordStats(const string16& word,
-                                                bool misspell) {
-  if (!metrics_enabled_)
-    return;
-  spellchecked_word_count_++;
-  if (misspell) {
-    misspelled_word_count_++;
-    // If an user misspelled, that user should be counted as a part of
-    // the population.  So we ensure to instantiate the histogram
-    // entries here at the first time.
-    if (misspelled_word_count_ == 1)
-      RecordReplacedWordStats(0);
-  }
-
-  int percentage = (100 * misspelled_word_count_) / spellchecked_word_count_;
-  UMA_HISTOGRAM_PERCENTAGE("SpellCheck.MisspellRatio", percentage);
-
-  // Collects actual number of checked words, excluding duplication.
-  MD5Digest digest;
-  MD5Sum(reinterpret_cast<const unsigned char*>(word.c_str()),
-         word.size() * sizeof(char16), &digest);
-  checked_word_hashes_.insert(MD5DigestToBase16(digest));
-  UMA_HISTOGRAM_COUNTS("SpellCheck.UniqueWords", checked_word_hashes_.size());
-}
-
-void SpellCheckHostImpl::OnHistogramTimerExpired() {
-  DCHECK(metrics_enabled_);
-  if (0 < spellchecked_word_count_) {
-    // Collects word checking rate, which is represented
-    // as a word count per hour.
-    base::TimeDelta since_start = base::Time::Now() - start_time_;
-    size_t checked_words_per_hour = spellchecked_word_count_
-        * base::TimeDelta::FromHours(1).InSeconds() / since_start.InSeconds();
-    UMA_HISTOGRAM_COUNTS("SpellCheck.CheckedWordsPerHour",
-                         checked_words_per_hour);
-  }
-}
-
-void SpellCheckHostImpl::RecordDictionaryCorruptionStats(bool corrupted) {
-  if (!metrics_enabled_)
-    return;
-  UMA_HISTOGRAM_BOOLEAN("SpellCheck.DictionaryCorrupted", corrupted);
-}
-
-void SpellCheckHostImpl::RecordSuggestionStats(int delta) {
-  if (!metrics_enabled_)
-    return;
-  suggestion_show_count_ += delta;
-  RecordReplacedWordStats(0);
-}
-
-void SpellCheckHostImpl::RecordReplacedWordStats(int delta) {
-  if (!metrics_enabled_)
-    return;
-  replaced_word_count_ += delta;
-
-  if (misspelled_word_count_) {
-    // zero |misspelled_word_count_| is possible when an extension
-    // gives the misspelling, which is not recorded as a part of this
-    // metrics.
-    int percentage = (100 * replaced_word_count_) / misspelled_word_count_;
-    UMA_HISTOGRAM_PERCENTAGE("SpellCheck.ReplaceRatio", percentage);
-  }
-
-  if (suggestion_show_count_) {
-    int percentage = (100 * replaced_word_count_) / suggestion_show_count_;
-    UMA_HISTOGRAM_PERCENTAGE("SpellCheck.SuggestionHitRatio", percentage);
-  }
-}
-
 void SpellCheckHostImpl::OnURLFetchComplete(const URLFetcher* source,
                                             const GURL& url,
                                             const net::URLRequestStatus& status,
@@ -427,7 +347,8 @@ void SpellCheckHostImpl::SaveDictionaryData() {
   // To prevent corrupted dictionary data from causing a renderer crash, scan
   // the dictionary data and verify it is sane before save it to a file.
   bool verified = hunspell::BDict::Verify(data_.data(), data_.size());
-  RecordDictionaryCorruptionStats(!verified);
+  if (metrics_)
+    metrics_->RecordDictionaryCorruptionStats(!verified);
   if (!verified) {
     LOG(ERROR) << "Failure to verify the downloaded dictionary.";
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
@@ -466,6 +387,10 @@ void SpellCheckHostImpl::SaveDictionaryData() {
   Initialize();
 }
 
+SpellCheckHostMetrics* SpellCheckHostImpl::GetMetrics() const {
+  return metrics_;
+}
+
 const base::PlatformFile& SpellCheckHostImpl::GetDictionaryFile() const {
   return file_;
 }
diff --git a/chrome/browser/spellcheck_host_impl.h b/chrome/browser/spellcheck_host_impl.h
index bf58c98..260b1cb 100644
--- a/chrome/browser/spellcheck_host_impl.h
+++ b/chrome/browser/spellcheck_host_impl.h
@@ -10,10 +10,7 @@
 #include <vector>
 
 #include "base/file_path.h"
-#include "base/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/time.h"
-#include "base/timer.h"
 #include "chrome/browser/spellcheck_host.h"
 #include "chrome/browser/spellcheck_host_observer.h"
 #include "content/common/notification_observer.h"
@@ -47,7 +44,7 @@ class SpellCheckHostImpl : public SpellCheckHost,
   SpellCheckHostImpl(SpellCheckHostObserver* observer,
                      const std::string& language,
                      net::URLRequestContextGetter* request_context_getter,
-                     bool metrics_enabled);
+                     SpellCheckHostMetrics* metrics);
 
   void Initialize();
 
@@ -91,25 +88,9 @@ class SpellCheckHostImpl : public SpellCheckHost,
   // Write a custom dictionary addition to disk.
   void WriteWordToCustomDictionary(const std::string& word);
 
-  // Collects a histogram for dictionary corruption rate
-  // to be uploaded via UMA
-  void RecordDictionaryCorruptionStats(bool corrupted);
-
-  // Collects time-dependent spell stats.
-  // This method is invoked by |histogram_timer_|.
-  void OnHistogramTimerExpired();
-
-  // Collects status of spellchecking enabling state, which is
-  // to be uploaded via UMA
-  virtual void RecordCheckedWordStats(const string16& word, bool misspell);
-
-  // Collects a histogram for misspelled word replacement
-  // to be uploaded via UMA
-  virtual void RecordReplacedWordStats(int delta);
-
-  // Collects a histogram for context menu showing as a spell correction
-  // attempt to be uploaded via UMA
-  virtual void RecordSuggestionStats(int delta);
+  // Returns a metrics counter associated with this object,
+  // or null when metrics recording is disabled.
+  virtual SpellCheckHostMetrics* GetMetrics() const;
 
   // URLFetcher::Delegate implementation.  Called when we finish downloading the
   // spellcheck dictionary; saves the dictionary to |data_|.
@@ -165,22 +146,8 @@ class SpellCheckHostImpl : public SpellCheckHost,
 
   NotificationRegistrar registrar_;
 
-  // True if metrics recording is enabled.
-  bool metrics_enabled_;
-
-  // Number of corrected words of checked words.
-  int misspelled_word_count_;
-  // Number of checked words.
-  int spellchecked_word_count_;
-  // Number of suggestion list showings.
-  int suggestion_show_count_;
-  // Number of misspelled words replaced by a user.
-  int replaced_word_count_;
-  // Time when first spellcheck happened.
-  base::Time start_time_;
-  // Set of checked words in the hashed form.
-  base::hash_set<std::string> checked_word_hashes_;
-  base::RepeatingTimer<SpellCheckHostImpl> histogram_timer_;
+  // An optional metrics counter given by the constructor.
+  SpellCheckHostMetrics* metrics_;
 };
 
 #endif  // CHROME_BROWSER_SPELLCHECK_HOST_IMPL_H_
diff --git a/chrome/browser/spellcheck_host_metrics.cc b/chrome/browser/spellcheck_host_metrics.cc
new file mode 100644
index 0000000..35ab129
--- /dev/null
+++ b/chrome/browser/spellcheck_host_metrics.cc
@@ -0,0 +1,93 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/spellcheck_host_metrics.h"
+
+#include "base/md5.h"
+#include "base/metrics/histogram.h"
+
+SpellCheckHostMetrics::SpellCheckHostMetrics()
+    : start_time_(base::Time::Now()) {
+  const uint64 kHistogramTimerDurationInMinutes = 30;
+  recording_timer_.Start(
+      base::TimeDelta::FromMinutes(kHistogramTimerDurationInMinutes),
+      this, &SpellCheckHostMetrics::OnHistogramTimerExpired);
+}
+
+SpellCheckHostMetrics::~SpellCheckHostMetrics() {
+}
+
+void SpellCheckHostMetrics::RecordCustomWordCountStats(size_t count) {
+  UMA_HISTOGRAM_COUNTS("SpellCheck.CustomWords", count);
+}
+
+void SpellCheckHostMetrics::RecordEnabledStats(bool enabled) {
+  UMA_HISTOGRAM_BOOLEAN("SpellCheck.Enabled", enabled);
+  // Because SpellCheckHost is instantiated lazily, the size of
+  // custom dictionary is unknown at this time. We mark it as -1 and
+  // record actual value later. See SpellCheckHost for more detail.
+  if (enabled)
+    RecordCustomWordCountStats(-1);
+}
+
+void SpellCheckHostMetrics::RecordCheckedWordStats(const string16& word,
+                                                   bool misspell) {
+  spellchecked_word_count_++;
+  if (misspell) {
+    misspelled_word_count_++;
+    // If an user misspelled, that user should be counted as a part of
+    // the population.  So we ensure to instantiate the histogram
+    // entries here at the first time.
+    if (misspelled_word_count_ == 1)
+      RecordReplacedWordStats(0);
+  }
+
+  int percentage = (100 * misspelled_word_count_) / spellchecked_word_count_;
+  UMA_HISTOGRAM_PERCENTAGE("SpellCheck.MisspellRatio", percentage);
+
+  // Collects actual number of checked words, excluding duplication.
+  MD5Digest digest;
+  MD5Sum(reinterpret_cast<const unsigned char*>(word.c_str()),
+         word.size() * sizeof(char16), &digest);
+  checked_word_hashes_.insert(MD5DigestToBase16(digest));
+  UMA_HISTOGRAM_COUNTS("SpellCheck.UniqueWords", checked_word_hashes_.size());
+}
+
+void SpellCheckHostMetrics::OnHistogramTimerExpired() {
+  if (0 < spellchecked_word_count_) {
+    // Collects word checking rate, which is represented
+    // as a word count per hour.
+    base::TimeDelta since_start = base::Time::Now() - start_time_;
+    size_t checked_words_per_hour = spellchecked_word_count_ *
+        base::TimeDelta::FromHours(1).InSeconds() / since_start.InSeconds();
+    UMA_HISTOGRAM_COUNTS("SpellCheck.CheckedWordsPerHour",
+                         checked_words_per_hour);
+  }
+}
+
+void SpellCheckHostMetrics::RecordDictionaryCorruptionStats(bool corrupted) {
+  UMA_HISTOGRAM_BOOLEAN("SpellCheck.DictionaryCorrupted", corrupted);
+}
+
+void SpellCheckHostMetrics::RecordSuggestionStats(int delta) {
+  suggestion_show_count_ += delta;
+  RecordReplacedWordStats(0);
+}
+
+void SpellCheckHostMetrics::RecordReplacedWordStats(int delta) {
+  replaced_word_count_ += delta;
+
+  if (misspelled_word_count_) {
+    // zero |misspelled_word_count_| is possible when an extension
+    // gives the misspelling, which is not recorded as a part of this
+    // metrics.
+    int percentage = (100 * replaced_word_count_) / misspelled_word_count_;
+    UMA_HISTOGRAM_PERCENTAGE("SpellCheck.ReplaceRatio", percentage);
+  }
+
+  if (suggestion_show_count_) {
+    int percentage = (100 * replaced_word_count_) / suggestion_show_count_;
+    UMA_HISTOGRAM_PERCENTAGE("SpellCheck.SuggestionHitRatio", percentage);
+  }
+}
diff --git a/chrome/browser/spellcheck_host_metrics.h b/chrome/browser/spellcheck_host_metrics.h
new file mode 100644
index 0000000..542952b
--- /dev/null
+++ b/chrome/browser/spellcheck_host_metrics.h
@@ -0,0 +1,77 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SPELLCHECK_HOST_METRICS_H_
+#define CHROME_BROWSER_SPELLCHECK_HOST_METRICS_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "base/hash_tables.h"
+#include "base/time.h"
+#include "base/timer.h"
+
+// A helper object for recording spell-check related histograms.
+// This class encapsulates histogram names and metrics API.
+// This also carries a set of counters for collecting histograms
+// and a timer for making a periodical summary.
+//
+// We expect a user of SpellCheckHost class to instantiate this object,
+// and pass the metrics object to SpellCheckHost's factory method.
+//
+//   metrics.reset(new SpellCheckHostMetrics());
+//   spell_check_host = SpellChecHost::Create(...., metrics.get());
+//
+// The lifetime of the object should be managed by a caller,
+// and the lifetime should be longer than SpellCheckHost instance
+// because SpellCheckHost will use the object.
+class SpellCheckHostMetrics {
+ public:
+  SpellCheckHostMetrics();
+  ~SpellCheckHostMetrics();
+
+  // Collects the number of words in the custom dictionary, which is
+  // to be uploaded via UMA.
+  void RecordCustomWordCountStats(size_t count);
+
+  // Collects status of spellchecking enabling state, which is
+  // to be uploaded via UMA
+  void RecordEnabledStats(bool enabled);
+
+  // Collects a histogram for dictionary corruption rate
+  // to be uploaded via UMA
+  void RecordDictionaryCorruptionStats(bool corrupted);
+
+  // Collects status of spellchecking enabling state, which is
+  // to be uploaded via UMA
+  void RecordCheckedWordStats(const string16& word, bool misspell);
+
+  // Collects a histogram for misspelled word replacement
+  // to be uploaded via UMA
+  void RecordReplacedWordStats(int delta);
+
+  // Collects a histogram for context menu showing as a spell correction
+  // attempt to be uploaded via UMA
+  void RecordSuggestionStats(int delta);
+
+  void OnHistogramTimerExpired();
+
+ private:
+  // Number of corrected words of checked words.
+  int misspelled_word_count_;
+  // Number of checked words.
+  int spellchecked_word_count_;
+  // Number of suggestion list showings.
+  int suggestion_show_count_;
+  // Number of misspelled words replaced by a user.
+  int replaced_word_count_;
+  // Time when first spellcheck happened.
+  base::Time start_time_;
+  // Set of checked words in the hashed form.
+  base::hash_set<std::string> checked_word_hashes_;
+  base::RepeatingTimer<SpellCheckHostMetrics> recording_timer_;
+};
+
+#endif  // CHROME_BROWSER_SPELLCHECK_HOST_METRICS_H_
diff --git a/chrome/browser/spellcheck_message_filter.cc b/chrome/browser/spellcheck_message_filter.cc
index 475440f..54de49e 100644
--- a/chrome/browser/spellcheck_message_filter.cc
+++ b/chrome/browser/spellcheck_message_filter.cc
@@ -7,6 +7,7 @@
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/spellcheck_host.h"
+#include "chrome/browser/spellcheck_host_metrics.h"
 #include "chrome/browser/spellchecker_platform_engine.h"
 #include "chrome/common/spellcheck_messages.h"
 #include "content/browser/renderer_host/render_process_host.h"
@@ -116,7 +117,7 @@ void SpellCheckMessageFilter::OnNotifyChecked(const string16& word,
   if (!host)
     return;  // Teardown.
   // Delegates to SpellCheckHost which tracks the stats of our spellchecker.
-  Profile* profile = host->profile();
-  if (profile->GetSpellCheckHost())
-    profile->GetSpellCheckHost()->RecordCheckedWordStats(word, misspelled);
+  SpellCheckHost* spellcheck_host = host->profile()->GetSpellCheckHost();
+  if (spellcheck_host && spellcheck_host->GetMetrics())
+    spellcheck_host->GetMetrics()->RecordCheckedWordStats(word, misspelled);
 }
diff --git a/chrome/browser/tab_contents/render_view_context_menu.cc b/chrome/browser/tab_contents/render_view_context_menu.cc
index 95a7bd3..f033949 100644
--- a/chrome/browser/tab_contents/render_view_context_menu.cc
+++ b/chrome/browser/tab_contents/render_view_context_menu.cc
@@ -37,6 +37,7 @@
 #include "chrome/browser/search_engines/template_url_service.h"
 #include "chrome/browser/search_engines/template_url_service_factory.h"
 #include "chrome/browser/spellcheck_host.h"
+#include "chrome/browser/spellcheck_host_metrics.h"
 #include "chrome/browser/spellchecker_platform_engine.h"
 #include "chrome/browser/translate/translate_manager.h"
 #include "chrome/browser/translate/translate_prefs.h"
@@ -747,8 +748,8 @@ void RenderViewContextMenu::AppendEditableItems() {
     // |spellcheck_host| can be null when the suggested word is
     // provided by Web SpellCheck API.
     SpellCheckHost* spellcheck_host = profile_->GetSpellCheckHost();
-    if (spellcheck_host)
-      spellcheck_host->RecordSuggestionStats(1);
+    if (spellcheck_host && spellcheck_host->GetMetrics())
+      spellcheck_host->GetMetrics()->RecordSuggestionStats(1);
   }
 
   // If word is misspelled, give option for "Add to dictionary"
@@ -1505,8 +1506,9 @@ void RenderViewContextMenu::ExecuteCommand(int id) {
           params_.dictionary_suggestions[id - IDC_SPELLCHECK_SUGGESTION_0]);
       // GetSpellCheckHost() can return null when the suggested word is
       // provided by Web SpellCheck API.
-      if (profile_->GetSpellCheckHost())
-        profile_->GetSpellCheckHost()->RecordReplacedWordStats(1);
+      SpellCheckHost* spellcheck_host = profile_->GetSpellCheckHost();
+      if (spellcheck_host && spellcheck_host->GetMetrics())
+        spellcheck_host->GetMetrics()->RecordReplacedWordStats(1);
       break;
     }
     case IDC_CHECK_SPELLING_OF_THIS_FIELD: {
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index e41557ee..5df1cc3 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -1920,6 +1920,8 @@
         'browser/spellcheck_host.h',
         'browser/spellcheck_host_impl.cc',
         'browser/spellcheck_host_impl.h',
+        'browser/spellcheck_host_metrics.cc',
+        'browser/spellcheck_host_metrics.h',
         'browser/spellcheck_message_filter.cc',
         'browser/spellcheck_message_filter.h',
         'browser/spellchecker_linux.cc',