Handful of related instant changes:

chrome/browser/instant/promo_counter.cc

Index: chrome/browser/instant/promo_counter.cc
diff --git a/chrome/browser/instant/promo_counter.cc b/chrome/browser/instant/promo_counter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..34c9b2fedca769f8f1a544050871436fceb1d7a0
--- /dev/null
+++ b/chrome/browser/instant/promo_counter.cc
@@ -0,0 +1,115 @@
+// Copyright (c) 2010 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/instant/promo_counter.h"
+
+#include "base/metrics/histogram.h"
+#include "base/values.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/profile.h"
+
+// Pref keys. These are relative to pref_key_.
+static const char* kShowKey = ".show";
+static const char* kNumSessionsKey = ".num_sessions";
+static const char* kInitialTimeKey = ".initial_time";
+
+// Values used for histograms. These are relative to histogram_key_.
+static const char* kHistogramHide = ".hide";
+static const char* kHistogramMaxSessions = ".max_sessions";
+static const char* kHistogramMaxTime = ".max_time";
+
+PromoCounter::PromoCounter(Profile* profile,
+                           const std::string& pref_key,
+                           const std::string& histogram_key,
+                           int max_sessions,
+                           int max_days)
+    : profile_(profile),
+      pref_key_(pref_key),
+      histogram_key_(histogram_key),
+      max_sessions_(max_sessions),
+      max_days_(max_days),
+      did_init_(false),
+      show_(false) {
+}
+
+PromoCounter::~PromoCounter() {
+}
+
+// static
+void PromoCounter::RegisterUserPrefs(PrefService* prefs,
+                                     const std::string& base_key) {
+  prefs->RegisterBooleanPref((base_key + kShowKey).c_str(), true);
+  prefs->RegisterIntegerPref((base_key + kNumSessionsKey).c_str(), 0);
+  prefs->RegisterInt64Pref((base_key + kInitialTimeKey).c_str(), 0);
+}
+
+bool PromoCounter::ShouldShow(base::Time current_time) {
+  if (!did_init_) {
+    did_init_ = true;
+    Init(current_time);
+  }
+
+  if (show_ && (current_time - initial_show_).InDays() >= max_days_)
+    MaxTimeLapsed(current_time);
+
+  return show_;
+}
+
+void PromoCounter::Hide() {
+  show_ = false;
+  did_init_ = true;
+  UMA_HISTOGRAM_CUSTOM_COUNTS(histogram_key_ + kHistogramHide,
+                              (base::Time::Now() - initial_show_).InHours(),
+                              1, max_days_ * 24, 24);
+  if (profile_->GetPrefs())
+    profile_->GetPrefs()->SetBoolean((pref_key_ + kShowKey).c_str(), false);
+}
+
+void PromoCounter::Init(base::Time current_time) {
+  PrefService* prefs = profile_->GetPrefs();
+  if (!prefs)
+    return;
+
+  show_ = prefs->GetBoolean((pref_key_ + kShowKey).c_str());
+  if (!show_)
+    return;
+
+  // The user hasn't chosen to opt in or out. Only show the opt-in if it's
+  // less than max_days_ since we first showed the opt-in, or the user hasn't
+  // launched the profile max_sessions_ times.
+  int session_count = prefs->GetInteger((pref_key_ + kNumSessionsKey).c_str());
+  int64 initial_show_int =
+      prefs->GetInt64((pref_key_ + kInitialTimeKey).c_str());
+  initial_show_ = base::Time(base::Time::FromInternalValue(initial_show_int));
+  if (initial_show_int == 0 || initial_show_ > current_time) {
+    initial_show_ = base::Time::Now();
+    prefs->SetInt64((pref_key_ + kInitialTimeKey).c_str(),
+                    initial_show_.ToInternalValue());
+  }
+  if (session_count >= max_sessions_) {
+    // Time check is handled in ShouldShow.
+    MaxSessionsEncountered(current_time);
+  } else {
+    // Up the session count.
+    prefs->SetInteger((pref_key_ + kNumSessionsKey).c_str(), session_count + 1);
+  }
+}
+
+void PromoCounter::MaxSessionsEncountered(base::Time current_time) {
+  show_ = false;
+  UMA_HISTOGRAM_CUSTOM_COUNTS(histogram_key_ + kHistogramMaxSessions,
+                              (current_time - initial_show_).InHours(), 1,
+                              max_days_ * 24, 24);
+  if (profile_->GetPrefs())
+    profile_->GetPrefs()->SetBoolean((pref_key_ + kShowKey).c_str(), false);
+}
+
+void PromoCounter::MaxTimeLapsed(base::Time current_time) {
+  show_ = false;
+  UMA_HISTOGRAM_CUSTOM_COUNTS(histogram_key_ + kHistogramMaxTime,
+                              (current_time - initial_show_).InHours(),
+                              1, max_days_ * 24, 24);
+  if (profile_->GetPrefs())
+    profile_->GetPrefs()->SetBoolean((pref_key_ + kShowKey).c_str(), false);
+}