Fix CrOS reverting to Save as PDF and random PDF preview fail

chrome/browser/resources/print_preview/data/destination_store.js

Index: chrome/browser/resources/print_preview/data/destination_store.js
diff --git a/chrome/browser/resources/print_preview/data/destination_store.js b/chrome/browser/resources/print_preview/data/destination_store.js
index a96778fcea849646b4df90b85660bf85ce4884fd..35705eb3f8bd6bc32c14b746b8e7a4a2b91e72de 100644
--- a/chrome/browser/resources/print_preview/data/destination_store.js
+++ b/chrome/browser/resources/print_preview/data/destination_store.js
@@ -669,8 +669,9 @@ cr.define('print_preview', function() {
       this.systemDefaultDestinationId_ = systemDefaultDestinationId;
       this.createLocalPdfPrintDestination_();
 
-      if (!this.appState_.selectedDestinationId ||
-          !this.appState_.selectedDestinationOrigin) {
+      if (!this.appState_.selectedDestination ||
+          !this.appState_.selectedDestination.id ||
+          !this.appState_.selectedDestination.origin) {
         var destinationMatch = this.convertToDestinationMatch_(
             serializedDefaultDestinationSelectionRulesStr);
         if (destinationMatch) {
@@ -680,8 +681,9 @@ cr.define('print_preview', function() {
       }
 
       if (!this.systemDefaultDestinationId_ &&
-          !(this.appState_.selectedDestinationId &&
-            this.appState_.selectedDestinationOrigin)) {
+          (!this.appState_.selectedDestination ||
+           !this.appState_.selectedDestination.id ||
+           !this.appState_.selectedDestination.origin)) {
         this.selectPdfDestination_();
         return;
       }
@@ -695,10 +697,12 @@ cr.define('print_preview', function() {
       var extensionName = '';
       var foundDestination = false;
       if (this.appState_.recentDestinations) {
-        // Run through the destinations backwards the most recently used is set
-        // as the initially selected destination.
-        for (var i = this.appState_.recentDestinations.length - 1; i >= 0;
-             i--) {
+        // Run through the destinations forward. As soon as we find a
+        // destination, don't select any future destinations, just mark
+        // them recent. Otherwise, there is a race condition between selecting
+        // destinations/updating the print ticket and this selecting a new
+        // destination that causes random print preview errors.
+        for (var i = 0; i < this.appState_.recentDestinations.length; i++) {
           origin = this.appState_.recentDestinations[i].origin;
           id = this.appState_.recentDestinations[i].id;
           account = this.appState_.recentDestinations[i].account || '';
@@ -712,10 +716,11 @@ cr.define('print_preview', function() {
               this.destinationMap_[this.getDestinationKey_(origin,
                                                            id, account)];
           if (candidate != null) {
-            this.selectDestination(candidate);
+            if (!foundDestination)
+              this.selectDestination(candidate);
             candidate.isRecent = true;
             foundDestination = true;
-          } else {
+          } else if (!foundDestination) {
             foundDestination = this.fetchPreselectedDestination_(
                                     origin,
                                     id,
@@ -933,11 +938,12 @@ cr.define('print_preview', function() {
      * @private
      */
     convertPreselectedToDestinationMatch_: function() {
-      if (this.appState_.selectedDestinationId &&
-          this.appState_.selectedDestinationOrigin) {
+      if (this.appState_.selectedDestination &&

[dpapad, 2016/11/19 01:37:58]

Can you package these three checks in a helper and re-use? They are currently
repeated in 3 places in this file (lines 672-674,  684-686, and here).

[rbpotter, 2016/11/19 02:44:58]

Done.

+          this.appState_.selectedDestination.id &&
+          this.appState_.selectedDestination.origin) {
         return this.createExactDestinationMatch_(
-            this.appState_.selectedDestinationOrigin,
-            this.appState_.selectedDestinationId);
+            this.appState_.selectedDestination.origin,
+            this.appState_.selectedDestination.id);
       }
       if (this.systemDefaultDestinationId_) {
         return this.createExactDestinationMatch_(
@@ -1338,8 +1344,9 @@ cr.define('print_preview', function() {
         this.insertDestination_(destination);
       }
 
-      if (existingDestination == this.selectedDestination_ ||
-          destination == this.selectedDestination_) {
+      if (this.selectedDestination_ &&
+          (existingDestination == this.selectedDestination_ ||
+           destination == this.selectedDestination_)) {
         this.appState_.persistSelectedDestination(this.selectedDestination_);
         cr.dispatchSimpleEvent(
             this,