Add Watch Conformance Tests (#2861)

Author: schmidt-sebastian

firebase-firestore/firebase-firestore.gradle

@@ -154,6 +154,9 @@ dependencies {
         exclude group: "com.google.firebase", module: "firebase-common"
     }
 
+    compileOnly 'com.google.auto.value:auto-value-annotations:1.6.6'
+    androidTestAnnotationProcessor 'com.google.auto.value:auto-value:1.6.5'
+
     testImplementation 'junit:junit:4.12'
     testImplementation 'androidx.test:core:1.2.0'
     testImplementation 'org.mockito:mockito-core:2.25.0'

firebase-firestore/src/androidTest/assets/conformance/README.md

@@ -6,4 +6,6 @@ The files were converted from text to binary encoding. Some files were split to
 memory consumption during the test run.
 
 The Protobuf definition is at 
-`firebase-firestore/src/proto/google/apphosting/datastore/testing/datastore_test_trace.proto`.
+`firebase-firestore/src/proto/google/apphosting/datastore/testing/datastore_test_trace.proto`.
+
+These tests are run as part of `:connectedCheck`.