Fix non-compliant rvalue ref code in chrome\updater\tag_unittest.cc.

This CL fixes a minor coding style issue.

https://google.github.io/styleguide/cppguide.html#Rvalue_references

According to the coding style, rvalue refs can only be used in a
couple of scenarios, and they do not include returning rvalue
references, or passing by rvalue reference, except in a specific
case.

This CL also fixes a couple of places where const pass by value
was used instead of pass by ref to const.

Since the initial intention of the code was to use
move semantics, that intention has been preserved, especially
to allow move semantics here:

  TagArgsBuilder& WithApp(AppArgs app) {
    this->inner_.apps.push_back(std::move(app));
    return *this;
  }

Due to how the code is used later on, move semantics for the
TagArgsBuilder is not really needed but the implementation
was retained to make TagArgsBuilder and AppArgsBuilder similar.

The CL code is slightly less efficient than the original code but
efficiency is not a first order concern in this module.

Bug: 1164718
Change-Id: I8b7ff4d225728b1ed00b0b387649672f5553c3f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2620401Reviewed-by: Joshua Pawlicki <waffles@chromium.org>
Commit-Queue: Sorin Jianu <sorin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842080}

chrome/updater/tag_unittest.cc

@@ -16,49 +16,49 @@ using updater::tagging::TagArgs;
 // Builder pattern helper to construct the TagArgs struct.
 class TagArgsBuilder {
  public:
-  TagArgs&& Build() { return std::move(inner_); }
+  TagArgs Build() { return std::move(inner_); }
 
-  TagArgsBuilder& WithBundleName(const std::string bundle_name) {
+  TagArgsBuilder& WithBundleName(const std::string& bundle_name) {
     this->inner_.bundle_name = bundle_name;
     return *this;
   }
-  TagArgsBuilder& WithInstallationId(const std::string installation_id) {
+  TagArgsBuilder& WithInstallationId(const std::string& installation_id) {
     this->inner_.installation_id = installation_id;
     return *this;
   }
-  TagArgsBuilder& WithBrandCode(const std::string brand_code) {
+  TagArgsBuilder& WithBrandCode(const std::string& brand_code) {
     this->inner_.brand_code = brand_code;
     return *this;
   }
-  TagArgsBuilder& WithClientId(const std::string client_id) {
+  TagArgsBuilder& WithClientId(const std::string& client_id) {
     this->inner_.client_id = client_id;
     return *this;
   }
-  TagArgsBuilder& WithExperimentLabels(const std::string experiment_labels) {
+  TagArgsBuilder& WithExperimentLabels(const std::string& experiment_labels) {
     this->inner_.experiment_labels = experiment_labels;
     return *this;
   }
-  TagArgsBuilder& WithReferralId(const std::string referral_id) {
+  TagArgsBuilder& WithReferralId(const std::string& referral_id) {
     this->inner_.referral_id = referral_id;
     return *this;
   }
-  TagArgsBuilder& WithLanguage(const std::string language) {
+  TagArgsBuilder& WithLanguage(const std::string& language) {
     this->inner_.language = language;
     return *this;
   }
-  TagArgsBuilder& WithFlighting(const bool flighting) {
+  TagArgsBuilder& WithFlighting(bool flighting) {
     this->inner_.flighting = flighting;
     return *this;
   }
-  TagArgsBuilder& WithBrowserType(const TagArgs::BrowserType browser_type) {
+  TagArgsBuilder& WithBrowserType(TagArgs::BrowserType browser_type) {
     this->inner_.browser_type = browser_type;
     return *this;
   }
-  TagArgsBuilder& WithUsageStatsEnable(const bool usage_stats_enable) {
+  TagArgsBuilder& WithUsageStatsEnable(bool usage_stats_enable) {
     this->inner_.usage_stats_enable = usage_stats_enable;
     return *this;
   }
-  TagArgsBuilder& WithApp(AppArgs&& app) {
+  TagArgsBuilder& WithApp(AppArgs app) {
     this->inner_.apps.push_back(std::move(app));
     return *this;
   }
@@ -70,36 +70,36 @@ class TagArgsBuilder {
 // Builder pattern helper to construct the AppArgs struct.
 class AppArgsBuilder {
  public:
-  explicit AppArgsBuilder(const std::string app_id) : inner_(app_id) {}
+  explicit AppArgsBuilder(const std::string& app_id) : inner_(app_id) {}
 
-  AppArgs&& Build() { return std::move(inner_); }
+  AppArgs Build() { return std::move(inner_); }
 
-  AppArgsBuilder& WithAppName(const std::string app_name) {
+  AppArgsBuilder& WithAppName(const std::string& app_name) {
     this->inner_.app_name = app_name;
     return *this;
   }
-  AppArgsBuilder& WithNeedsAdmin(const AppArgs::NeedsAdmin needs_admin) {
+  AppArgsBuilder& WithNeedsAdmin(AppArgs::NeedsAdmin needs_admin) {
     this->inner_.needs_admin = needs_admin;
     return *this;
   }
-  AppArgsBuilder& WithAp(const std::string ap) {
+  AppArgsBuilder& WithAp(const std::string& ap) {
     this->inner_.ap = ap;
     return *this;
   }
   AppArgsBuilder& WithEncodedInstallerData(
-      const std::string encoded_installer_data) {
+      const std::string& encoded_installer_data) {
     this->inner_.encoded_installer_data = encoded_installer_data;
     return *this;
   }
-  AppArgsBuilder& WithInstallDataIndex(const std::string install_data_index) {
+  AppArgsBuilder& WithInstallDataIndex(const std::string& install_data_index) {
     this->inner_.install_data_index = install_data_index;
     return *this;
   }
-  AppArgsBuilder& WithExperimentLabels(const std::string experiment_labels) {
+  AppArgsBuilder& WithExperimentLabels(const std::string& experiment_labels) {
     this->inner_.experiment_labels = experiment_labels;
     return *this;
   }
-  AppArgsBuilder& WithUntrustedData(const std::string untrusted_data) {
+  AppArgsBuilder& WithUntrustedData(const std::string& untrusted_data) {
     this->inner_.untrusted_data = untrusted_data;
     return *this;
   }