Keep "Add" button in "Add to Homescreen" dialog disabled till launcher icon is fetched

chrome/android/java/src/org/chromium/chrome/browser/webapps/AddToHomescreenDialog.java

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/AddToHomescreenDialog.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/AddToHomescreenDialog.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/AddToHomescreenDialog.java
index 7d46b67c73e07a7bc5ad52479b9b09f14535cbdf..49b3aa251dc25e8470226600f7b72b0c764239e6 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/AddToHomescreenDialog.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/AddToHomescreenDialog.java
@@ -95,7 +95,7 @@ public class AddToHomescreenDialog {
                 progressBarView.setVisibility(View.GONE);
                 iconView.setVisibility(View.VISIBLE);
                 iconView.setImageBitmap(icon);
-                dialog.getButton(DialogInterface.BUTTON_POSITIVE).setEnabled(true);
+                updateAddButtonEnabledState(dialog, dialogHelper, input);
             }
         });
 
@@ -110,11 +110,7 @@ public class AddToHomescreenDialog {
 
             @Override
             public void afterTextChanged(Editable editableText) {
-                if (TextUtils.isEmpty(editableText)) {
-                    dialog.getButton(DialogInterface.BUTTON_POSITIVE).setEnabled(false);
-                } else {
-                    dialog.getButton(DialogInterface.BUTTON_POSITIVE).setEnabled(true);
-                }
+                updateAddButtonEnabledState(dialog, dialogHelper, input);
             }
         });
 
@@ -133,8 +129,7 @@ public class AddToHomescreenDialog {
         dialog.setOnShowListener(new DialogInterface.OnShowListener() {
             @Override
             public void onShow(DialogInterface d) {
-                dialog.getButton(DialogInterface.BUTTON_POSITIVE).setEnabled(
-                        dialogHelper.isInitialized());
+                updateAddButtonEnabledState(dialog, dialogHelper, input);
             }
         });
 
@@ -150,4 +145,16 @@ public class AddToHomescreenDialog {
 
         dialog.show();
     }
+
+    /**
+     * Updates whether the dialog's OK button is enabled.
+     * @param dialog The dialog whose "OK" button to enable or disable.
+     * @param helper
+     * @param input The dialog's text field.
+     */
+    public static void updateAddButtonEnabledState(
+            AlertDialog dialog, AddToHomescreenDialogHelper helper, EditText input) {
+        boolean enable = helper.isInitialized() && !TextUtils.isEmpty(input.getText());
+        dialog.getButton(DialogInterface.BUTTON_POSITIVE).setEnabled(enable);
+    }
 }