Avoiding creation of new string for component version.

base::Version constructor already takes a std::string, so no need to
pass in result of c_str() which would just create a second std::string.

Review URL: https://codereview.chromium.org/1280673002

Cr-Commit-Position: refs/heads/master@{#342383}

components/component_updater/default_component_installer.cc

@@ -84,7 +84,7 @@ bool DefaultComponentInstaller::Install(const base::DictionaryValue& manifest,
                                         const base::FilePath& unpack_path) {
   std::string manifest_version;
   manifest.GetStringASCII("version", &manifest_version);
-  base::Version version(manifest_version.c_str());
+  base::Version version(manifest_version);
   if (!version.IsValid())
     return false;
   if (current_version_.CompareTo(version) > 0)