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 237bba967a6013be8075d1ae87087d520386b79e..638b51f27f2fd13b7daf6b67fa1e04e111e68bd1 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
@@ -27,6 +27,7 @@
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
+#include "base/threading/worker_pool.h"
 #include "base/values.h"
 #include "chrome/browser/app_mode/app_mode_utils.h"
 #include "chrome/browser/browser_process.h"
@@ -45,6 +46,7 @@
 #include "chrome/browser/ui/browser_tabstrip.h"
 #include "chrome/browser/ui/chrome_select_file_policy.h"
 #include "chrome/browser/ui/scoped_tabbed_browser_displayer.h"
+#include "chrome/browser/ui/webui/print_preview/extension_printer_handler.h"
 #include "chrome/browser/ui/webui/print_preview/print_preview_ui.h"
 #include "chrome/browser/ui/webui/print_preview/printer_handler.h"
 #include "chrome/browser/ui/webui/print_preview/sticky_settings.h"
@@ -670,6 +672,10 @@ void PrintPreviewHandler::RegisterMessages() {
       "getExtensionPrinterCapabilities",
       base::Bind(&PrintPreviewHandler::HandleGetExtensionPrinterCapabilities,
                  base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "grantExtensionUsbPrinterAccess",
+      base::Bind(&PrintPreviewHandler::HandleGrantExtensionUsbPrinterAccess,
+                 base::Unretained(this)));
   RegisterForGaiaCookieChanges();
 }
 
@@ -744,6 +750,22 @@ void PrintPreviewHandler::HandleGetExtensionPrinters(
       &PrintPreviewHandler::OnGotPrintersForExtension, 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;
@@ -1683,11 +1705,10 @@ void PrintPreviewHandler::FillPrinterDescription(
 #endif  // defined(ENABLE_SERVICE_DISCOVERY)
 
 void PrintPreviewHandler::EnsureExtensionPrinterHandlerSet() {
-  if (extension_printer_handler_.get())
-    return;
-
-  extension_printer_handler_ =
-      PrinterHandler::CreateForExtensionPrinters(Profile::FromWebUI(web_ui()));
+  if (!extension_printer_handler_.get()) {
+    extension_printer_handler_.reset(new ExtensionPrinterHandler(
+        Profile::FromWebUI(web_ui()), base::WorkerPool::GetTaskRunner(true)));
+  }
 }
 
 void PrintPreviewHandler::OnGotPrintersForExtension(
@@ -1697,6 +1718,20 @@ void PrintPreviewHandler::OnGotPrintersForExtension(
                                    base::FundamentalValue(done));
 }
 
+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) {