Domain Reliability: Include config_version in uploads

Echo the config's version in uploads based on the config, so the server
can judge what frequency/type of reports to expect.

BUG=356791

Review URL: https://codereview.chromium.org/290473005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271466 0039d316-1c4b-4281-b951-d872f2087c98

components/domain_reliability/context.cc

@@ -272,6 +272,7 @@ scoped_ptr<const Value> DomainReliabilityContext::CreateReport(
   }
 
   DictionaryValue* report_value = new DictionaryValue();
+  report_value->SetString("config_version", config().version);
   report_value->SetString("reporter", upload_reporter_string_);
   report_value->Set("resource_reports", resources_value);
 

components/domain_reliability/context.h

@@ -52,7 +52,7 @@ class DOMAIN_RELIABILITY_EXPORT DomainReliabilityContext {
       uint32* successful_requests_out,
       uint32* failed_requests_out) const;
 
-  const DomainReliabilityConfig& config() { return *config_.get(); }
+  const DomainReliabilityConfig& config() const { return *config_.get(); }
 
   // Maximum number of beacons queued per context; if more than this many are
   // queued; the oldest beacons will be removed.

components/domain_reliability/context_unittest.cc

@@ -158,7 +158,9 @@ TEST_F(DomainReliabilityContextTest, ReportUpload) {
   DomainReliabilityBeacon beacon = MakeBeacon(&time_);
   context_.OnBeacon(url, beacon);
 
-  const char* kExpectedReport = "{\"reporter\":\"test-reporter\","
+  // N.B.: Assumes max_delay is 5 minutes.
+  const char* kExpectedReport = "{\"config_version\":\"1\","
+      "\"reporter\":\"test-reporter\","
       "\"resource_reports\":[{\"beacons\":[{\"http_response_code\":200,"
       "\"request_age_ms\":300250,\"request_elapsed_ms\":250,\"server_ip\":"
       "\"127.0.0.1\",\"status\":\"ok\"}],\"failed_requests\":0,"