Implement install module verification metric.

chrome/browser/install_module_verifier_win.cc

+// Copyright (c) 2013 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/install_module_verifier_win.h"
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/metrics/sparse_histogram.h"
+#include "base/strings/utf_string_conversions.h"
+#include "base/values.h"
+#include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/enumerate_modules_model_win.h"
+#include "chrome/browser/expected_install_modules_win.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_source.h"
+
+namespace {
+
+// Callback for VerifyModules that reports matching module IDs via UMA.
+void OnModuleMatch(size_t module_index) {
+  UMA_HISTOGRAM_SPARSE_SLOWLY("InstallVerifier.ModuleMatch", module_index);
+}
+
+// Helper to extract canonical loaded module names from the EnumerateModulesWin
+// output and then verify the results.
+void VerifyEnumeratedModules(const base::ListValue& module_list) {
+  std::set<base::string16> canonical_module_names;
+  ExtractLoadedModuleNames(module_list, &canonical_module_names);
+  VerifyModules(canonical_module_names, base::Bind(&OnModuleMatch));
+}
+
+// Waits for NOTIFICATION_MODULE_LIST_ENUMERATED, which indicates that
+// EnumerateModulesWin has completed its work. Retrieves the enumerated module
+// list and processes it.
+class InstallModuleVerifier : private content::NotificationObserver {

[Finnur, 2013/09/25 12:54:22]

Private inheritance is against the style guide:
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Inheri...

You can still put the implementation of Observe in the private clause, I
believe.

[erikwright (departed), 2013/09/25 19:58:08]

Done. Yes you can make Observe private but it is merely documentation. On the
other hand, since the constructor is private there is no way to get an instance
of this class so it's not a big deal.

+ public:
+  // Creates an instance that will wait for module enumeration to complete,
+  // process the results, and then delete itself.
+  static void WaitForModuleList() {
+    // Will delete itself when scan results are available.
+    new InstallModuleVerifier();
+  }
+
+ private:
+  // content::NotificationObserver implementation.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE {
+    DCHECK_EQ(type, chrome::NOTIFICATION_MODULE_LIST_ENUMERATED);
+    EnumerateModulesModel* model =
+        content::Source<EnumerateModulesModel>(source).ptr();
+    scoped_ptr<base::ListValue> module_list(model->GetModuleList());
+
+    if (module_list.get())
+      VerifyEnumeratedModules(*module_list);
+
+    delete this;
+  }
+
+  InstallModuleVerifier() {
+    notification_registrar_.Add(this,
+                                chrome::NOTIFICATION_MODULE_LIST_ENUMERATED,
+                                content::NotificationService::AllSources());
+  }
+
+  ~InstallModuleVerifier() {}
+
+  content::NotificationRegistrar notification_registrar_;
+
+  DISALLOW_COPY_AND_ASSIGN(InstallModuleVerifier);
+};
+
+}  // namespace
+
+void BeginModuleVerification() {
+  scoped_ptr<base::ListValue> module_list(
+      EnumerateModulesModel::GetInstance()->GetModuleList());
+  if (module_list.get()) {
+    VerifyEnumeratedModules(*module_list);
+  } else {
+    InstallModuleVerifier::WaitForModuleList();
+    EnumerateModulesModel::GetInstance()->ScanNow();
+  }
+}
+
+void ExtractLoadedModuleNames(const base::ListValue& module_list,
+                              std::set<base::string16>* module_names) {
+  DCHECK(module_names);
+
+  // EnumerateModulesModel produces a list of dictionaries.
+  // Each dictionary corresponds to a module and exposes a number of properties.
+  // We care only about 'type' and 'name'.
+  for (size_t i = 0; i < module_list.GetSize(); ++i) {
+    const base::DictionaryValue* module_dictionary = NULL;
+    if (!module_list.GetDictionary(i, &module_dictionary))
+      continue;
+    ModuleEnumerator::ModuleType module_type =
+        ModuleEnumerator::LOADED_MODULE;
+    if (!module_dictionary->GetInteger(
+            "type", reinterpret_cast<int*>(&module_type)) ||
+        module_type != ModuleEnumerator::LOADED_MODULE) {
+      continue;
+    }
+    std::string utf8_module_name;
+    if (!module_dictionary->GetString("name", &utf8_module_name))
+      continue;
+    base::string16 module_name = base::UTF8ToUTF16(utf8_module_name);
+    base::string16 canonical_module_name = CanonicalizeModuleName(module_name);
+    module_names->insert(canonical_module_name);
+  }
+}
+
+void VerifyModules(const std::set<base::string16>& canonical_module_names,
+                   const base::Callback<void(size_t)>& delegate) {
+  for (size_t module_index = 0; kExpectedInstallModules[module_index] != NULL;
+       ++module_index) {
+    if (canonical_module_names.find(kExpectedInstallModules[module_index]) !=
+        canonical_module_names.end()) {
+      delegate.Run(module_index);
+    }
+  }
+}