Factor out JsonOptions into a struct

Change-Id: I2441069e86ea2eb95d8e1952be7c2a7a43036c74
diff --git a/aos/events/event_loop_param_test.cc b/aos/events/event_loop_param_test.cc
index d0ca3ee..dc7c5d0 100644
--- a/aos/events/event_loop_param_test.cc
+++ b/aos/events/event_loop_param_test.cc
@@ -767,7 +767,7 @@
 
   // Confirm that we have the right number of reports, and the contents are
   // sane.
-  VLOG(1) << FlatbufferToJson(report, true);
+  VLOG(1) << FlatbufferToJson(report, {.multi_line = true});
 
   EXPECT_EQ(report.message().name()->string_view(), "primary");
 
@@ -1181,7 +1181,7 @@
     }
   }
 
-  VLOG(1) << FlatbufferToJson(report, true);
+  VLOG(1) << FlatbufferToJson(report, {.multi_line = true});
 
   EXPECT_EQ(report.message().name()->string_view(), "primary");
 
@@ -1245,7 +1245,7 @@
     }
   }
 
-  LOG(INFO) << FlatbufferToJson(primary_report, true);
+  LOG(INFO) << FlatbufferToJson(primary_report, {.multi_line = true});
 
   EXPECT_EQ(primary_report.message().name()->string_view(), "primary");
 
@@ -1327,7 +1327,7 @@
   }
 
   // Check the watcher report.
-  VLOG(1) << FlatbufferToJson(primary_report, true);
+  VLOG(1) << FlatbufferToJson(primary_report, {.multi_line = true});
 
   EXPECT_EQ(primary_report.message().name()->string_view(), "primary");
 
@@ -1397,7 +1397,7 @@
     }
   }
 
-  VLOG(1) << FlatbufferToJson(primary_report, true);
+  VLOG(1) << FlatbufferToJson(primary_report, {.multi_line = true});
 
   EXPECT_EQ(primary_report.message().name()->string_view(), "primary");