Add "Checking" spinner for server-side shipping address validation.

chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentOption.java

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentOption.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentOption.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentOption.java
index 99d17c526572ed9d3c542d3ac67813c429309efe..96689d96a9ba0f06b56ea1b8fa67ae866092776a 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentOption.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentOption.java
@@ -18,6 +18,7 @@ public class PaymentOption {
     private final String mLabel;
     private final String mSublabel;
     private final int mIcon;
+    private boolean mIsValid = true;
 
     /**
      * Constructs a payment option.
@@ -63,4 +64,21 @@ public class PaymentOption {
     public int getDrawableIconId() {
         return mIcon;
     }
+
+    /**
+     * Marks this option as invalid. For example, this can be a shipping address that's not served
+     * by the merchant.
+     */
+    public void setInvalid() {
+        mIsValid = false;
+    }
+
+    /**
+     * Returns whether this option is valid.
+     *
+     * @return True if this option is valid.
+     */
+    public boolean isValid() {
+        return mIsValid;
+    }
 }