Fix Firestore's snapshot_metadata_android_test

[dconeybe]

For some reason, the call to env.FindClass() was failing because it couldn't find the class. So I updated the code to use our new, modern JNI wrapper and it all worked. I'm not sure why but I'm happy with the result.

[github-actions]

✅  Integration test succeeded!

Requested by @dconeybe on commit 3d3255d
Last updated: Tue May 18 14:57:47 PDT 2021
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[wu-hui]

The PR looks good.

But have you tried to figure out what are being executed btw the two different implementation?

[dconeybe]

But have you tried to figure out what are being executed btw the two different implementation?

No, I did not figure out what was being done differently. Although I'm curious and would like to dig into it, I feel that my time is better spent elsewhere.

[dconeybe]

But have you tried to figure out what are being executed btw the two different implementation?

No, I did not figure out what was being done differently. Although I'm curious and would like to dig into it, I feel that my time is better spent elsewhere.

I think I know why the call to env.FindClass() was failing. It's a known issue/limitation of the Android JNI APIs where it was using a ClassLoader that only had the built-in standard libraries available. The workaround would have been to use the ClassLoader retrieved from another class. This logic is already implemented in a helper function of whose existence I was unaware at the time: app_framework::FindClass():

firebase-cpp-sdk/testing/sample_framework/src/android/android_app_framework.cc

Line 82 in 8925603

jclass FindClass(JNIEnv* env, jobject activity_object, const char* class_name) {

So I probably could have just swapped out the call to env.FindClass() with app_framework::FindClass().