platform2: sweep the lint errors identified by the updated linter

cpplint.py has been updated and identified new issues in existing
code. Stuff like overridden functions that specify 'override' should
not be marked as 'virtual', and constructors with no parameters
should not be marked as 'explicit'.

BUG=None
TEST=cpplint.py `find ./platform2 -name *.cc -or -name *.h`

Change-Id: Ibb9de43286d874d076ffd5ebb1b13c36ec794f01
Reviewed-on: https://chromium-review.googlesource.com/211950
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/stub_storage.h b/stub_storage.h
index a7d8619..2af2bce 100644
--- a/stub_storage.h
+++ b/stub_storage.h
@@ -18,83 +18,81 @@
  public:
   virtual ~StubStorage() {}
 
-  virtual bool Flush() override { return false; }
-  virtual std::set<std::string> GetGroups() const override {
-    return {};
-  }
-  virtual std::set<std::string> GetGroupsWithKey(
+  bool Flush() override { return false; }
+  std::set<std::string> GetGroups() const override { return {}; }
+  std::set<std::string> GetGroupsWithKey(
       const std::string &key) const override {
     return {};
   }
-  virtual std::set<std::string> GetGroupsWithProperties(
+  std::set<std::string> GetGroupsWithProperties(
       const KeyValueStore &properties) const override {
     return {};
   }
-  virtual bool ContainsGroup(const std::string &group) const override {
+  bool ContainsGroup(const std::string &group) const override {
     return false;
   }
-  virtual bool DeleteKey(const std::string &group, const std::string &key)
+  bool DeleteKey(const std::string &group, const std::string &key)
       override { return false; }
-  virtual bool DeleteGroup(const std::string &group) override { return false; }
-  virtual bool SetHeader(const std::string &header) override { return false; }
-  virtual bool GetString(const std::string &group,
-                         const std::string &key,
-                         std::string *value) const override {
+  bool DeleteGroup(const std::string &group) override { return false; }
+  bool SetHeader(const std::string &header) override { return false; }
+  bool GetString(const std::string &group,
+                 const std::string &key,
+                 std::string *value) const override {
     return false;
   }
-  virtual bool SetString(const std::string &group,
-                         const std::string &key,
-                         const std::string &value) override {
+  bool SetString(const std::string &group,
+                 const std::string &key,
+                 const std::string &value) override {
     return false;
   }
-  virtual bool GetBool(const std::string &group,
-                       const std::string &key,
-                       bool *value) const override {
+  bool GetBool(const std::string &group,
+               const std::string &key,
+               bool *value) const override {
     return false;
   }
-  virtual bool SetBool(const std::string &group,
-                       const std::string &key,
-                       bool value) override {
+  bool SetBool(const std::string &group,
+               const std::string &key,
+               bool value) override {
     return false;
   }
-  virtual bool GetInt(const std::string &group,
-                      const std::string &key,
-                      int *value) const override {
+  bool GetInt(const std::string &group,
+              const std::string &key,
+              int *value) const override {
     return false;
   }
-  virtual bool SetInt(const std::string &group,
-                      const std::string &key,
-                      int value) override {
+  bool SetInt(const std::string &group,
+              const std::string &key,
+              int value) override {
     return false;
   }
-  virtual bool GetUint64(const std::string &group,
-                         const std::string &key,
-                         uint64_t *value) const override {
+  bool GetUint64(const std::string &group,
+                 const std::string &key,
+                 uint64_t *value) const override {
     return false;
   }
-  virtual bool SetUint64(const std::string &group,
-                         const std::string &key,
-                         uint64_t value) override {
+  bool SetUint64(const std::string &group,
+                 const std::string &key,
+                 uint64_t value) override {
     return false;
   }
-  virtual bool GetStringList(const std::string &group,
-                             const std::string &key,
-                             std::vector<std::string> *value) const override {
+  bool GetStringList(const std::string &group,
+                     const std::string &key,
+                     std::vector<std::string> *value) const override {
     return false;
   }
-  virtual bool SetStringList(const std::string &group,
-                             const std::string &key,
-                             const std::vector<std::string> &value) override {
+  bool SetStringList(const std::string &group,
+                     const std::string &key,
+                     const std::vector<std::string> &value) override {
     return false;
   }
-  virtual bool GetCryptedString(const std::string &group,
-                                const std::string &key,
-                                std::string *value) override {
+  bool GetCryptedString(const std::string &group,
+                        const std::string &key,
+                        std::string *value) override {
     return false;
   }
-  virtual bool SetCryptedString(const std::string &group,
-                                const std::string &key,
-                                const std::string &value) override {
+  bool SetCryptedString(const std::string &group,
+                        const std::string &key,
+                        const std::string &value) override {
     return false;
   }
 };