Add GoogleUtilities README (#1541)

GoogleUtilities.podspec

@@ -8,8 +8,7 @@ Internal Google Utilities including Network, Reachability Environment, Logger, a
 other Google CocoaPods. They're not intended for direct public usage.
                        DESC
 
-# TODO update homepage link with GoogleUtilities is moved to another repo.
-  s.homepage         = 'https://github.com/firebase/firebase-ios-sdk'
+  s.homepage         = 'https://github.com/firebase/firebase-ios-sdk/tree/master/GoogleUtilities'
   s.license          = { :type => 'Apache', :file => 'LICENSE' }
   s.authors          = 'Google, Inc.'
 

GoogleUtilities/README.md

@@ -0,0 +1,26 @@
+# Google Utilities
+
+## Overview
+
+The GoogleUtilities pod is a set of utilities organized into CocoaPods subspecs.
+See the [podspec](../GoogleUtilities.podspec) for a summary of what utilities
+are currently included. They're used by Firebase and other Google products.
+
+Direct usage by non-Google products and CocoaPods is **NOT** currently
+recommended or supported.
+
+## Development
+
+Follow the subsequent instructions to develop, debug, and unit test
+GoogleUtilities:
+
+```
+$ git clone git@github.com:firebase/firebase-ios-sdk.git
+$ cd firebase-ios-sdk/GoogleUtilities/Example
+$ pod update
+$ open GoogleUtilities.xcworkspace
+```
+
+### Running Unit Tests
+
+Choose the one of the Tests* schemes and press Command-u.

README.md

@@ -4,6 +4,10 @@ This repository contains a subset of the Firebase iOS SDK source. It currently
 includes FirebaseCore, FirebaseAuth, FirebaseDatabase, FirebaseFirestore,
 FirebaseFunctions, FirebaseMessaging and FirebaseStorage.
 
+The repository also includes GoogleUtilities source. The
+[GoogleUtilities](GoogleUtilities/README.md) pod is
+a set of utilities used by Firebase and other Google products.
+
 Firebase is an app development platform with tools to help you build, grow and
 monetize your app. More information about Firebase can be found at
 [https://firebase.google.com](https://firebase.google.com).