Use cammelCase for all service extension variables

runtime/observatory/tests/service/file_service_test.dart

Index: runtime/observatory/tests/service/file_service_test.dart
diff --git a/runtime/observatory/tests/service/file_service_test.dart b/runtime/observatory/tests/service/file_service_test.dart
index 47611b1841e5bf5380d7ead1d80e6ae99b84e2c2..22b58272b9d59657863c190105f4e8c00914ec05 100644
--- a/runtime/observatory/tests/service/file_service_test.dart
+++ b/runtime/observatory/tests/service/file_service_test.dart
@@ -79,22 +79,22 @@ var fileTests = [
       var writing = await isolate.invokeRpcNoUpgrade(
            '__getFileByID', { 'id' : result['data'][0]['id'] });
 
-      expect(writing['total_read'], equals(0));
-      expect(writing['read_count'], equals(0));
-      expect(writing['write_count'], equals(3));
-      expect(writing['total_written'], equals(3));
-      expect(writing['last_write'], greaterThan(0));
-      expect(writing['last_read'], equals(0));
+      expect(writing['totalRead'], equals(0));
+      expect(writing['readCount'], equals(0));
+      expect(writing['writeCount'], equals(3));
+      expect(writing['totalWritten'], equals(3));
+      expect(writing['lastWrite'], greaterThan(0));
+      expect(writing['lastRead'], equals(0));
 
       var reading = await isolate.invokeRpcNoUpgrade(
           '__getFileByID', { 'id' : result['data'][1]['id'] });
 
-      expect(reading['total_read'], equals(5));
-      expect(reading['read_count'], equals(5));
-      expect(reading['write_count'], equals(0));
-      expect(reading['total_written'], equals(0));
-      expect(reading['last_write'], equals(0));
-      expect(reading['last_read'], greaterThan(0));
+      expect(reading['totalRead'], equals(5));
+      expect(reading['readCount'], equals(5));
+      expect(reading['writeCount'], equals(0));
+      expect(reading['totalWritten'], equals(0));
+      expect(reading['lastWrite'], equals(0));
+      expect(reading['lastRead'], greaterThan(0));
 
     } finally {
       await isolate.invokeRpcNoUpgrade('__cleanup', {});