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..7ac736f440c58be1b12f1ae52af65144aea3c36e 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 mValid = true;

[gone, 2016/06/13 20:34:03]

mIsValid

[please use gerrit instead, 2016/06/13 21:59:08]

Done.

 
     /**
      * 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() {
+        mValid = false;
+    }
+
+    /**
+     * Returns whether this option is valid.
+     *
+     * @return True if this option is valid.
+     */
+    public boolean isValid() {
+        return mValid;
+    }
 }