* Port FSTMemoryPersistence to C++ (#3754)
* Add local::Persistence
* Add MemoryPersistence
* Add MemoryEagerReferenceDelegate
* Make LruDelegate extend ReferenceDelegate
This enables downcasting to LruDelegate in tests that need to do so.
* Add MemoryLruReferenceDelegate
* Don't double-count document key size.
* Port FSTLevelDB to C++ (#3755)
* Add LevelDbPersistence
Note that Apple-specific initialization has been partitioned off in
anticipation of being able to run this code on non-Apple platforms.
* Add LevelDbLruReferenceDelegate
* Migrate to C++ Persistence (1/2) (#3756)
* Use C++ Persistence classes in FSTLocalStore
* Remove ReferenceDelegateBridge
* Cut src over to C++ persistence types
* Remove Objective-C requirement from some classes
... that no longer require it.
* Migrate to C++ Persistence (2/2) (#3757)
* Remove LruDelegateBridge
* Update test initialization of persistence components
In particular, ensure that there's always an owner for the Persistence
instance, which wasn't always handled explicitly in the Objective-C
version of the tests.
* Largely mechanical changes to tests
* Remove Objective-C persistence classes
* Forward declare util::Status when possible (#3761)
* Add a header dedicated to forward declarations for util::Status
* Use status_fwd.h wherever possible
This simplifies the import process back into google3 and allows us to add additional directories to the project without needing to update the project files for each directory we add. This shows up most clearly in the change to Firestore/Example/Firestore.xcodeproj/project.pbxproj: this no longer needs to list essentially every directory in the project as a header search path.
* Clang-format configuration for C++ files
* Add support C++-only sources to the podspec
* Podspec support for fully qualified imports
* xcodeproj changes for fully-qualified imports
* Use fully-qualified imports in Firestore sources
Gil