Add onGetUsbPrinterInfoRequested event to printerProvider API.

chrome/browser/ui/webui/print_preview/print_preview_handler.cc

Index: chrome/browser/ui/webui/print_preview/print_preview_handler.cc
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
index 3be7765d2e09a66fba97a310db91432bb86b81ed..cd5200be7173f9251e617c083f6bb255da1fccbe 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
@@ -676,6 +676,10 @@ void PrintPreviewHandler::RegisterMessages() {
       "getExtensionPrinterCapabilities",
       base::Bind(&PrintPreviewHandler::HandleGetExtensionPrinterCapabilities,
                  base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "grantExtensionUsbPrinterAccess",
+      base::Bind(&PrintPreviewHandler::HandleGrantExtensionUsbPrinterAccess,
+                 base::Unretained(this)));
   RegisterForGaiaCookieChanges();
 }
 
@@ -756,6 +760,22 @@ void PrintPreviewHandler::HandleGetExtensionUsbPrinters(
       &PrintPreviewHandler::OnGotExtensionUsbPrinters, base::Unretained(this)));
 }
 
+void PrintPreviewHandler::HandleGrantExtensionUsbPrinterAccess(
+    const base::ListValue* args) {
+  std::string extension_id;
+  bool ok = args->GetString(0, &extension_id);
+  DCHECK(ok);
+  int device_id;
+  ok = args->GetInteger(1, &device_id);
+  DCHECK(ok);
+
+  EnsureExtensionPrinterHandlerSet();
+  extension_printer_handler_->StartGrantUsbPrinterAccess(
+      extension_id, device_id,
+      base::Bind(&PrintPreviewHandler::OnGotExtensionUsbPrinterInfo,
+                 base::Unretained(this), extension_id, device_id));
+}
+
 void PrintPreviewHandler::HandleGetExtensionPrinterCapabilities(
     const base::ListValue* args) {
   std::string printer_id;
@@ -1713,6 +1733,20 @@ void PrintPreviewHandler::OnGotExtensionUsbPrinters(
   web_ui()->CallJavascriptFunction("onExtensionUsbPrintersAdded", printers);
 }
 
+void PrintPreviewHandler::OnGotExtensionUsbPrinterInfo(
+    const std::string& extension_id,
+    int device_id,
+    const base::DictionaryValue& printer_info) {
+  if (printer_info.empty()) {
+    web_ui()->CallJavascriptFunction("failedToGetExtensionUsbPrinterInfo",
+                                     base::StringValue(extension_id),
+                                     base::FundamentalValue(device_id));
+    return;
+  }
+
+  web_ui()->CallJavascriptFunction("onExtensionUsbPrinterAdded", printer_info);
+}
+
 void PrintPreviewHandler::OnGotExtensionPrinterCapabilities(
     const std::string& printer_id,
     const base::DictionaryValue& capabilities) {