* XdsBootstrap: move two more methods out of the interface
* Automated change: Fix sanity tests
* XdsClient: add unit test
* Automated change: Fix sanity tests
* fix memory leaks
* add helper method
* add unsubscription
* add test for multiple subscriptions
* clang-format
* fix build
* fix flakiness
* add checking for other node fields
* add v2 test
* add response builder
* add test for update from server
* add test for update containing only changed resources
* clang-format
* fix build
* add test for resource not existing upon subscription
* add test for stream closed by server
* add test for multiple watchers for the same resource
* add test for connection failure
* clang-format
* add test for resources wrapped in Resource wrapper message
* add test for resource validation failure
* add test for multiple invalid resources, and fix a case in XdsClient
* add test for validation failure for already-cached resource
* add test for server not resending resources after stream disconnect
* clang-format
* fix XdsClient to report channel errors to newly started watchers
* fix XdsClient to send cached errors/does-not-exists to newly started watchers
* fix watcher to ensure events arrive in the expected order
* fix tests
* clang-format
* add test for multiple resource types
* fix xds_cluster_e2e_test
* Automated change: Fix sanity tests
* cleanup
* add federation tests
* clang-format
* remove now-unnecessary XdsCertificateProviderPluginMapInterface
* code review comments
* simplify XdsResourceType::Decode() API
* XdsClient: add unit tests for XdsClusterResourceType
* add XdsClient with gRPC bootstrap config
* add LB policy tests
* started adding CertificateProvider tests
* update for recent API changes
* fix merge bugs
* xDS resource validation: identify extensions by type_url instead of name
* fix build
* migrate to ValidationErrors
* add xds_common_types_test
* finish TLS tests and add LRS tests
* move ScopedExperimentalEnvVar to its own library and remove redundant e2e tests
* add circuit breaking and outlier detection tests
* add validation to outlier detection LB policy parsing
* clang-format
* Automated change: Fix sanity tests
* fix signedness
* fix sanity
* fix sanity
* iwyu
* update code for XdsResourceTypeImpl changes
Co-authored-by: markdroth <markdroth@users.noreply.github.com>