Implement main CertificateReportingService code and add unit tests.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index 1c7ce3b7eb720ea5a87af2bd1158e39a2da07c23..0c5402e3ecf559859775e5d260e361cd070815e8 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -670,7 +670,7 @@ class SafeBrowsingSSLCertReporter : public SSLCertReporter {
       : safe_browsing_ui_manager_(safe_browsing_ui_manager) {}
   ~SafeBrowsingSSLCertReporter() override {}
 
-  // SSLCertReporter implementation
+  // SSLCertReporter methods:
   void ReportInvalidCertificateChain(
       const std::string& serialized_report) override {
     if (safe_browsing_ui_manager_) {
@@ -678,6 +678,7 @@ class SafeBrowsingSSLCertReporter : public SSLCertReporter {
           serialized_report, base::Bind(&base::DoNothing));
     }
   }
+  void OnDidNotSendReport() override {}
 
  private:
   const scoped_refptr<safe_browsing::SafeBrowsingUIManager>