Signin: Reuse existing "update gms" dialogs when possible.

chrome/android/java/src/org/chromium/chrome/browser/externalauth/UserRecoverableErrorHandler.java

Index: chrome/android/java/src/org/chromium/chrome/browser/externalauth/UserRecoverableErrorHandler.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/externalauth/UserRecoverableErrorHandler.java b/chrome/android/java/src/org/chromium/chrome/browser/externalauth/UserRecoverableErrorHandler.java
index ba1c4ceb6b8b188de3546066e0dba9693bd63fc0..136ce4521996775578ce90bc063274d2416cbe9c 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/externalauth/UserRecoverableErrorHandler.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/externalauth/UserRecoverableErrorHandler.java
@@ -130,6 +130,11 @@ public abstract class UserRecoverableErrorHandler {
         private Dialog mDialog;
 
         /**
+         * Last error code from Google Play Services.
+         */
+        private int mErrorCode;
+
+        /**
          * Create a new Modal Dialog handler for the specified activity and error code. The
          * specified activity may be used to launch the dialog via
          * {@link Activity#startActivityForResult(android.content.Intent, int)} and also to receive
@@ -149,10 +154,18 @@ public abstract class UserRecoverableErrorHandler {
          */
         @Override
         protected final void handle(final Context context, final int errorCode) {
-            mDialog = GoogleApiAvailability.getInstance().getErrorDialog(
-                    mActivity, errorCode, NO_RESPONSE_REQUIRED);
+            // Assume old dialogs generated by the same error handler are obsolete when an error
+            // with a different error code is encountered.
+            if (mErrorCode != errorCode) {
+                cancelDialog();
+            }
+            if (mDialog == null) {
+                mDialog = GoogleApiAvailability.getInstance().getErrorDialog(
+                        mActivity, errorCode, NO_RESPONSE_REQUIRED);
+                mErrorCode = errorCode;
+            }
+            // This can happen if |errorCode| is ConnectionResult.SERVICE_INVALID.
             if (mDialog != null) {
-                // This can happen if |errorCode| is ConnectionResult.SERVICE_INVALID.
                 mDialog.show();
             }
             sErrorHandlerActionHistogramSample.record(ERROR_HANDLER_ACTION_MODAL_DIALOG);
@@ -161,6 +174,7 @@ public abstract class UserRecoverableErrorHandler {
         public void cancelDialog() {
             if (mDialog != null) {
                 mDialog.cancel();
+                mDialog = null;
             }
         }
     }