Update GooglePayLauncher Constructor Params (#876)

* Update constructor and doc strings

* Fix wording

GooglePay/src/main/java/com/braintreepayments/api/GooglePayLauncher.java

@@ -1,15 +1,15 @@
 package com.braintreepayments.api;
 
+import androidx.activity.ComponentActivity;
 import androidx.activity.result.ActivityResultLauncher;
 import androidx.activity.result.ActivityResultRegistry;
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
 import androidx.fragment.app.Fragment;
-import androidx.fragment.app.FragmentActivity;
 import androidx.lifecycle.LifecycleOwner;
 
 /**
- * Responsible for launching the Google Pay dialog
+ * Responsible for launching the Google Pay payment sheet
  */
 public class GooglePayLauncher {
 
@@ -18,13 +18,29 @@ public class GooglePayLauncher {
 
     private static final String GOOGLE_PAY_RESULT = "com.braintreepayments.api.GooglePay.RESULT";
 
+    /**
+     * Used to launch the Google Pay payment sheet from within an Android Fragment. This class must be
+     * instantiated before the Fragment is created.
+     *
+     * @param fragment the Android Fragment from which you will launch the Google Pay payment sheet
+     * @param callback a {@link GooglePayLauncherCallback} to receive the result of the Google Pay
+     *                 payment flow
+     */
     public GooglePayLauncher(@NonNull Fragment fragment,
                              @NonNull GooglePayLauncherCallback callback) {
         this(fragment.getActivity().getActivityResultRegistry(), fragment.getViewLifecycleOwner(),
                 callback);
     }
 
-    public GooglePayLauncher(@NonNull FragmentActivity activity,
+    /**
+     * Used to launch the Google Pay payment sheet from within an Android Activity. This class must be
+     * instantiated before the Activity is created.
+     *
+     * @param activity the Android Activity from which you will launch the Google Pay payment sheet
+     * @param callback a {@link GooglePayLauncherCallback} to receive the result of the Google Pay
+     *                 payment flow
+     */
+    public GooglePayLauncher(@NonNull ComponentActivity activity,
                              @NonNull GooglePayLauncherCallback callback) {
         this(activity.getActivityResultRegistry(), activity, callback);
     }
@@ -36,6 +52,15 @@ public GooglePayLauncher(@NonNull FragmentActivity activity,
                 new GooglePayActivityResultContract(), callback::onResult);
     }
 
+    /**
+     * Launches the Google Pay payment sheet. This method cannot be called until the lifecycle of
+     * the Fragment or Activity used to instantiate your {@link GooglePayLauncher} has reached the
+     * CREATED state.
+     *
+     * @param googlePayPaymentAuthRequestParams the {@link GooglePayPaymentAuthRequestParams}
+     *                                          received from invoking
+     *                                          {@link GooglePayClient#createPaymentAuthRequest(GooglePayRequest, GooglePayPaymentAuthRequestCallback)}
+     */
     public void launch(GooglePayPaymentAuthRequestParams googlePayPaymentAuthRequestParams) {
         activityLauncher.launch(googlePayPaymentAuthRequestParams);
     }