Add unit tests for the CLD component installer

chrome/browser/component_updater/cld_component_installer.h

 // Copyright 2014 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_COMPONENT_UPDATER_CLD_COMPONENT_INSTALLER_H_
 #define CHROME_BROWSER_COMPONENT_UPDATER_CLD_COMPONENT_INSTALLER_H_
 
+#include <string>
+#include <vector>
+
 #include "base/files/file_path.h"
+#include "base/gtest_prod_util.h"
+#include "chrome/browser/component_updater/default_component_installer.h"
 
 namespace component_updater {
 
 class ComponentUpdateService;
 
+// Visible for testing. No need to instantiate this class directly.
+class CldComponentInstallerTraits : public ComponentInstallerTraits {
+ public:
+  CldComponentInstallerTraits();
+  virtual ~CldComponentInstallerTraits() {}
+
+ private:
+  friend class CldComponentInstallerTest;  // For access within SetUp()
+  FRIEND_TEST_ALL_PREFIXES(CldComponentInstallerTest, ComponentReady);
+  FRIEND_TEST_ALL_PREFIXES(CldComponentInstallerTest, GetBaseDirectory);
+  FRIEND_TEST_ALL_PREFIXES(CldComponentInstallerTest, GetHash);
+  FRIEND_TEST_ALL_PREFIXES(CldComponentInstallerTest, GetInstalledPath);
+  FRIEND_TEST_ALL_PREFIXES(CldComponentInstallerTest, GetName);
+  FRIEND_TEST_ALL_PREFIXES(CldComponentInstallerTest, OnCustomInstall);
+  FRIEND_TEST_ALL_PREFIXES(CldComponentInstallerTest, SetLatestCldDataFile);
+  FRIEND_TEST_ALL_PREFIXES(CldComponentInstallerTest, VerifyInstallation);
+
+  // The following methods override ComponentInstallerTraits.
+  virtual bool CanAutoUpdate() const OVERRIDE;
+  virtual bool OnCustomInstall(const base::DictionaryValue& manifest,
+                               const base::FilePath& install_dir) OVERRIDE;
+  virtual bool VerifyInstallation(
+      const base::FilePath& install_dir) const OVERRIDE;
+  virtual void ComponentReady(
+      const base::Version& version,
+      const base::FilePath& path,
+      scoped_ptr<base::DictionaryValue> manifest) OVERRIDE;
+  virtual base::FilePath GetBaseDirectory() const OVERRIDE;
+  virtual void GetHash(std::vector<uint8>* hash) const OVERRIDE;
+  virtual std::string GetName() const OVERRIDE;
+
+  base::FilePath GetInstalledPath(const base::FilePath& base) const;
+  void SetLatestCldDataFile(const base::FilePath& path);
+  DISALLOW_COPY_AND_ASSIGN(CldComponentInstallerTraits);
+};
+
+// Call once during startup to make the component update service aware of
+// the CLD component.
 void RegisterCldComponent(ComponentUpdateService* cus);
 
-// Places the path to the latest CLD data file into the specified path object.
-// Returns true if and only if the file has been observed to exist at least
-// once and was valid when it was observed; if the function returns false, the
-// path parameter is not modified. This function is threadsafe.
-bool GetLatestCldDataFile(base::FilePath* path);
+// Returns the path to the latest CLD data file into the specified path object,
+// or an empty path if the CLD data file has not been observed yet.
+// This function is threadsafe.
+base::FilePath GetLatestCldDataFile();
 
 }  // namespace component_updater
 
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_CLD_COMPONENT_INSTALLER_H_