Introduce concept of provisional destinations to print preview

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 6f52f234d593b34e24ddd3a133d9404ac0ee2635..60d8d0ecc9fce62b0186e4b27f86d8c78989cf96 100644
--- a/chrome/browser/resources/print_preview/data/destination_store.js
+++ b/chrome/browser/resources/print_preview/data/destination_store.js
@@ -199,6 +199,8 @@ cr.define('print_preview', function() {
     DESTINATION_SELECT: 'print_preview.DestinationStore.DESTINATION_SELECT',
     DESTINATIONS_INSERTED:
         'print_preview.DestinationStore.DESTINATIONS_INSERTED',
+    PROVISIONAL_DESTINATION_RESOLVED:
+        'print_preview.DestinationStore.PROVISIONAL_DESTINATION_RESOLVED',
     CACHED_SELECTED_DESTINATION_INFO_READY:
         'print_preview.DestinationStore.CACHED_SELECTED_DESTINATION_INFO_READY',
     SELECTED_DESTINATION_CAPABILITIES_READY:
@@ -461,6 +463,9 @@ cr.define('print_preview', function() {
             this, DestinationStore.EventType.DESTINATION_SELECT);
         return;
       }
+
+      assert(!destination.isProvisional, 'Selecting provisonal destination');
+
       // Update and persist selected destination.
       this.selectedDestination_ = destination;
       this.selectedDestination_.isRecent = true;
@@ -511,6 +516,17 @@ cr.define('print_preview', function() {
       }
     },
 
+    resolveProvisionalDestination: function(destination) {
+      assert(
+          destination.provisionalType ==
+              print_preview.Destination.ProvisionalType.NEEDS_USB_PERMISSION,
+          'Provisional type cannot be resolved.');
+      assert(destination.usbId != null,
+             'Resolving provisional destination without USB ID.');
+      this.nativeLayer_.grantUsbExtensionPermission(
+          destination.id, destination.extensionId, destination.usbId);
+    },
+
     /**
      * Selects 'Save to PDF' destination (since it always exists).
      * @private
@@ -613,6 +629,36 @@ cr.define('print_preview', function() {
       this.waitForRegisterDestination_ = id;
     },
 
+    resolveProvisionalDestination_: function(evt) {
+      var provisionalDestinationIndex = -1;
+      var provisionalDestination = null;
+      for (var i = 0; i < this.destinations_.length; ++i) {
+        if (evt.provisionalId == this.destinations_[i].id) {
+          provisionalDestinationIndex = i;
+          provisionalDestination = this.destinations_[i];
+          break;
+        }
+      }
+
+      if (!provisionalDestination)
+        return;
+
+      this.destinations_.splice(provisionalDestinationIndex, 1);
+      this.destinationMap_[this.getKey_(provisionalDestination)] = undefined;
+
+      var destination = evt.destination ?
+          print_preview.ExtensionDestinationParser.parse(evt.destination) :
+          null;
+      if (destination)
+        this.insertIntoStore_(destination);
+
+      var event = new Event(
+          DestinationStore.EventType.PROVISIONAL_DESTINATION_RESOLVED);
+      event.provisionalId = evt.provisionalId;
+      event.destination = destination;
+      this.dispatchEvent(event);
+    },
+
     /**
      * Inserts {@code destination} to the data store and dispatches a
      * DESTINATIONS_INSERTED event.
@@ -782,6 +828,10 @@ cr.define('print_preview', function() {
           this.nativeLayer_,
           print_preview.NativeLayer.EventType.EXTENSION_CAPABILITIES_SET,
           this.onExtensionCapabilitiesSet_.bind(this));
+      this.tracker_.add(
+          this.nativeLayer_,
+          print_preview.NativeLayer.EventType.EXTENSION_USB_PRINTER_RESOLVED,
+          this.resolveProvisionalDestination_.bind(this));
     },
 
     /**
@@ -1008,14 +1058,29 @@ cr.define('print_preview', function() {
      * @private
      */
     onExtensionPrintersAdded_: function(event) {
-      // Filter out printers enumerated from providers' "usbPrinters" manifest
-      // key for now.
-      var filteredPrinters = event.printers.filter(function(printer) {
-        return 'extensionId' in printer;
-      });
-      this.insertDestinations_(filteredPrinters.map(function(printer) {
-        return print_preview.ExtensionDestinationParser.parse(printer);
-      }));
+      event.printers.forEach(function(printer) {
+        if (!printer.needsUsbPermission) {
+          this.insertDestinations_([
+            print_preview.ExtensionDestinationParser.parse(printer)
+          ]);
+          return;
+        }
+
+        // Add provisional extension destinations that support a USB printer.
+        printer.extensions.forEach(function(extension) {
+          var provisionalDest = print_preview.ExtensionDestinationParser.parse({
+            id: extension.printerId,
+            extensionId: extension.extensionId,
+            extensionName: extension.extensionName,
+            name: printer.name,
+            usbDevice: printer.usbDevice
+          });
+
+          provisionalDest.provisionalType =
+              print_preview.Destination.ProvisionalType.NEEDS_USB_PERMISSION;
+          this.insertDestinations_([provisionalDest]);
+        }.bind(this));
+      }.bind(this));
 
       if (event.done && this.isExtensionDestinationSearchInProgress_) {
         clearTimeout(this.extensionSearchTimeout_);