use namespace aliases instead.
This makes the Objective-C code much more like what it's going to end up
being like when translated to C++: headers will include classes declared
in a namespace relative to firebase::firestore so everything else will
be named relative to firebase::firestore.
Meanwhile the using statements in the headers were causing us to miss
adding using statements in source files which was moving us away from
where we wanted to be.
Also eliminate most usages of `FSTDocumentKey`, remove most methods from the Objective-C class and make it just a wrapper over `DocumentKey`. The only usage that cannot be directly replaced by C++ `DocumentKey` is in `FSTFieldValue`.
* Drop acknowledged mutations in schema migration (#1818)
Drop acknowledged mutations in schema migration as part of removing held write acks.
Port of firebase/firebase-js-sdk#1149
* Change removeMutationBatch to remove a single batch (#1955)
* Update Firestore Generated Protos
* Adding UnknownDocument and hasCommittedMutations (#1971)
* Removing held write batch handling from LocalStore (#1997)
* View changes for held write acks (#2004)
* Held Write Acks Unit Test Fixes (#2008)
* Held Write Ack Removal Spec Tests (#2018)
* Fix integration test
* remove conversions in `Local` and `Remote`
* replace `FSTSnapshotVersion` in `Model`
* replace `FSTSnapshotVersion` in the rest
* let test check equal with C++ equal
* fix newly added code
* address changes
* naively remove FSTPath import and source/test files.
* port FieldPath, part I
* port FieldPath, part II
* port ResourcePath, part I
* port ResourcePath, part II
* the grand commit to fix build errors
* use testutil:: helper instead of those from FSTHelpers
* fix test and lint
* use c_str in errmsg directly
* fix
* fix
* make code clean
* fix integration test I missed
* fix to avoid naming collision in preprocessor
* address changes
* address changes
* address changes
* fix: fieldMask are actually shared with different context.
* address changes
* add converter function between two DocumentKey implementations
* add unit test
* address changes
* fix lint
* using DocumentKey in model except for the container types `FSTDocumentDictionary`, `FSTDocumentKeySet`, and `FSTDocumentVersionDictionary`
* change other place w.r.t. the use of `DocumentKey` in model
* update parameter of test helpers from NSString to string_view
* revert a temporary change used in debug
* address changes
* naively remove FSTPath import and source/test files.
* port FieldPath, part I
* port FieldPath, part II
* port ResourcePath, part I
* port ResourcePath, part II
* the grand commit to fix build errors
* use testutil:: helper instead of those from FSTHelpers
* fix test and lint
* use c_str in errmsg directly
* fix
* fix
* make code clean
* fix integration test I missed
* fix to avoid naming collision in preprocessor
* address changes
* address changes
* address changes
* fix: fieldMask are actually shared with different context.
* address changes
* address changes
* Move all Firestore files to Objective-C++
* Update project file references
* Don't use module imports from Objective-C++
* Use extern "C" for C-accessible globals
* Work around more stringent type checking in Objective-C++
* NSMutableDictionary ivars aren't implicitly casted to NSDictionary
* FSTMaybeDocument callback can't be passed a function that accepts
FSTDocument
* NSComparisonResult can't be multiplied by -1 without casting
* Add a #include <inttypes.h> where needed
* Avoid using C++ keywords as variables
* Remove #if __cplusplus guards
Gil