web-start/src/index.js (14 lines):
	- line 52: alert('TODO: Implement Google Sign-In');
	- line 53: // TODO 1: Sign in Firebase with credential from the Google user.
	- line 58: // TODO 2: Sign out of Firebase.
	- line 63: // TODO 3: Subscribe to the user's signed-in status
	- line 68: // TODO 4: Return the user's profile pic URL.
	- line 73: // TODO 5: Return the user's display name.
	- line 78: // TODO 6: Return true if a user is signed-in.
	- line 83: // TODO 7: Push a new message to Cloud Firestore.
	- line 88: // TODO 8: Load and listen for new messages.
	- line 94: // TODO 9: Posts a new image as a message.
	- line 99: // TODO 10: Save the device token in Cloud Firestore
	- line 104: // TODO 11: Request permissions to send notifications.
	- line 346: // TODO 0: Initialize Firebase
	- line 348: // TODO 12: Initialize Firebase Performance Monitoring


performance-monitoring/src/index.js (7 lines):
	- line 51: // TODO: Import the Firebase Performance Monitoring library here.
	- line 140: // TODO: Create custom trace to monitor image upload.
	- line 143: // TODO: Record image size.
	- line 146: // TODO: Record image MIME type.
	- line 149: // TODO: Start the “timer” for the custom trace.
	- line 157: // TODO: Stop the “timer” for the custom trace.
	- line 445: // TODO: Initialize Firebase Performance Monitoring.


performance-monitoring-start/src/index.js (7 lines):
	- line 51: // TODO: Import the Firebase Performance Monitoring library here.
	- line 136: // TODO: Create custom trace to monitor image upload.
	- line 138: // TODO: Record image size.
	- line 140: // TODO: Record image MIME type.
	- line 142: // TODO: Start the “timer” for the custom trace.
	- line 149: // TODO: Stop the “timer” for the custom trace.
	- line 436: // TODO: Initialize Firebase Performance Monitoring.


performance-monitoring-start/public/index.html (3 lines):
	- line 49: <!-- TODO: Mark the starting of `timer` for loading App Styling script. -->
	- line 53: <!-- TODO: Mark the ending of `timer` for loading App Styling script. Measure the duration from starting to ending. -->
	- line 56: <!-- TODO: Enable First Input Delay polyfill library. -->


performance-monitoring/public/index.html (3 lines):
	- line 49: <!-- TODO: Mark the starting of `timer` for loading App Styling script. -->
	- line 53: <!-- TODO: Mark the ending of `timer` for loading App Styling script. Measure the duration from starting to ending. -->
	- line 59: <!-- TODO: Enable First Input Delay polyfill library. -->


web-start/src/firebase-config.js (1 line):
	- line 10: /* TODO: ADD YOUR FIREBASE CONFIGURATION OBJECT HERE */


performance-monitoring-start/src/firebase-config.js (1 line):
	- line 10: /* TODO: ADD YOUR FIREBASE CONFIGURATION OBJECT HERE */


performance-monitoring/src/firebase-config.js (1 line):
	- line 10: /* TODO: ADD YOUR FIREBASE CONFIGURATION OBJECT HERE */


web/public/index.html (1 line):
	- line 52: <!-- TODO: Enable First Input Delay polyfill library. -->


web/src/firebase-config.js (1 line):
	- line 10: /* TODO: ADD YOUR FIREBASE CONFIGURATION OBJECT HERE */


web-start/public/index.html (1 line):
	- line 52: <!-- TODO: Enable First Input Delay polyfill library. -->


web-start/src/firebase-messaging-sw.js (1 line):
	- line 1: // TODO: Set up Firebase Cloud Messaging service worker