* Add the Truth dependency
* Port Junit test to Truth in the package `com.google.gson` of the module `gson`
* Replace the `assertThat(e.getMessage()).isEqualTo(...)"` with `assertThat(e).hasMessageThat().isEqualTo(...)`
* Minor fixes
* Make Object and JsonElement deserialization iterative
Often when Object and JsonElement are deserialized the format of the JSON
data is unknown and it might come from an untrusted source. To avoid a
StackOverflowError from maliciously crafted JSON, deserialize Object and
JsonElement iteratively instead of recursively.
Concept based on 51fd2faab7
But implementation is not based on it.
* Improve imports grouping
* Address review feedback
The most notable impact of this change is that it adds several new public APIs:
- The TypeAdapter abstract class
- The TypeAdapter.Factory interface
- Four new methods on GsonBuilder to register streaming TypeAdapters (via Factory, via Class, via TypeToken, and as a type hierarchy)
- Three new methods on Gson to lookup streaming TypeAdapters (by type, by class, and to get the next type adapter)
Still outstanding:
- Write beautiful prose to document the new APIs above
- Change GsonBuilder's precedence so that both old and new-style type adapters are registered in one lot