Open source FIAM headless SDK (#2312)

FirebaseInAppMessaging.podspec

@@ -0,0 +1,39 @@
+Pod::Spec.new do |s|
+  s.name             = 'FirebaseInAppMessaging'
+  s.version          = '0.12.0'
+  s.summary          = 'Firebase In-App Messaging for iOS'
+
+  s.description      = <<-DESC
+FirebaseInAppMessaging is the headless component of Firebase In-App Messaging on iOS client side.
+See more product details at https://firebase.google.com/products/in-app-messaging/ about Firebase In-App Messaging.
+                       DESC
+
+  s.homepage         = 'https://firebase.google.com'
+  s.license          = { :type => 'Apache', :file => 'LICENSE' }
+  s.authors          = 'Google, Inc.'
+
+  s.source           = {
+    :git => 'https://github.com/firebase/firebase-ios-sdk.git',
+    :tag => s.version.to_s
+  }
+  s.social_media_url = 'https://twitter.com/Firebase'
+  s.ios.deployment_target = '8.0'
+
+  s.cocoapods_version = '>= 1.4.0'
+  s.static_framework = true
+  s.prefix_header_file = false
+
+  base_dir = "Firebase/InAppMessaging/"
+  s.source_files = base_dir + '**/*.[mh]'
+  s.public_header_files = base_dir + 'Public/*.h'
+
+  s.pod_target_xcconfig = { 'GCC_PREPROCESSOR_DEFINITIONS' =>
+      '$(inherited) ' +
+      'FIRInAppMessaging_LIB_VERSION=' + String(s.version)
+  }
+
+  s.dependency 'FirebaseCore'
+  s.ios.dependency 'FirebaseAnalytics'
+  s.ios.dependency 'FirebaseAnalyticsInterop'
+  s.dependency 'FirebaseInstanceID'
+end