Firebase Core Plugin

Pigeon interface
requires firebase cpp sdk: https://github.com/firebase/firebase-cpp-sdk to exist and be built prior.
This plugin is included when the following variable is set:

  -DBUILD_PLUGIN_CLOUD_FIRESTORE=ON
  -DBUILD_PLUGIN_CLOUD_AUTH=ON
  -DBUILD_PLUGIN_CLOUD_STORAGE=ON    

Building Firebase C++ SDK

pip3 install absl-py

GCC

git clone https://github.com/firebase/firebase-cpp-sdk.git
cd firebase-cpp-sdk
mkdir build && cd build
cmake .. -DFIREBASE_USE_BORINGSSL=YES -DFIREBASE_LINUX_USE_CXX11_ABI=ON
make -j

Clang

git clone https://github.com/firebase/firebase-cpp-sdk.git
cd firebase-cpp-sdk
mkdir build && cd build
CC=/usr/bin/clang CXX=/usr/bin/clang++ cmake .. -DFIREBASE_USE_BORINGSSL=YES -DFIREBASE_LINUX_USE_CXX11_ABI=ON -DCMAKE_CXX_FLAGS="-stdlib=libc++ -Wno-deprecated-builtins"
make -j

Functional Test Case

git clone https://github.com/firebase/flutterfire.git
flutterfire/packages/firebase_core/firebase_core/example

Change options to default to Android when Linux

index 58b54d65f..1c44a0ccf 100644
--- a/packages/firebase_core/firebase_core/example/lib/firebase_options.dart
+++ b/packages/firebase_core/firebase_core/example/lib/firebase_options.dart
@@ -24,6 +24,7 @@ class DefaultFirebaseOptions {
       return web;
     }
     switch (defaultTargetPlatform) {
+      case TargetPlatform.linux:
       case TargetPlatform.android:
         return android;
       case TargetPlatform.iOS:

Run flutter application:

flutter run -d desktop-homescreen

Monitor terminal output for interaction with application

Reference Firebase C++ SDK Build

-DFIREBASE_CPP_SDK_DIR=<path to firebase-sdk-sdk root folder>
-DFIREBASE_SDK_LIBDIR=<path to firebase-sdk-sdk build root folder>