Support inf and -inf as well

Turns out if you serialize a schema to json which has a default of
infinity, you can't deserialize it again.  Add support for the infinity
there.

Change-Id: I4b55a293ffbbde118b33f5cc90f4e22cf43d19d9
diff --git a/aos/json_to_flatbuffer_test.cc b/aos/json_to_flatbuffer_test.cc
index 9dc12d2..aa259df 100644
--- a/aos/json_to_flatbuffer_test.cc
+++ b/aos/json_to_flatbuffer_test.cc
@@ -79,10 +79,20 @@
   EXPECT_TRUE(JsonAndBack("{ \"foo_enum_nonconsecutive\": \"Big\" }"));
 }
 
+// Tests that Inf is handled correctly
+TEST_F(JsonToFlatbufferTest, Inf) {
+  EXPECT_TRUE(JsonAndBack("{ \"foo_float\": inf }"));
+  EXPECT_TRUE(JsonAndBack("{ \"foo_float\": -inf }"));
+  EXPECT_TRUE(JsonAndBack("{ \"foo_double\": inf }"));
+  EXPECT_TRUE(JsonAndBack("{ \"foo_double\": -inf }"));
+}
+
 // Tests that NaN is handled correctly
 TEST_F(JsonToFlatbufferTest, Nan) {
   EXPECT_TRUE(JsonAndBack("{ \"foo_float\": nan }"));
   EXPECT_TRUE(JsonAndBack("{ \"foo_float\": -nan }"));
+  EXPECT_TRUE(JsonAndBack("{ \"foo_double\": nan }"));
+  EXPECT_TRUE(JsonAndBack("{ \"foo_double\": -nan }"));
 }
 
 // Tests that we can handle decimal points.