List printers managed by extensions in print preview

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 335e6083faa72754eed0543e151c3244f205b2d6..b9cf3f3e7794d1437265518f58f1c92a2d863fd9 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
@@ -89,6 +89,10 @@
 #include "chrome/browser/local_discovery/privet_constants.h"
 #endif
 
+#if defined(ENABLE_EXTENSIONS)
+#include "extensions/browser/api/printer_provider/printer_provider_api.h"
+#endif
+
 using content::BrowserThread;
 using content::RenderViewHost;
 using content::WebContents;
@@ -647,6 +651,14 @@ void PrintPreviewHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback("getPrivetPrinterCapabilities",
       base::Bind(&PrintPreviewHandler::HandleGetPrivetPrinterCapabilities,
                  base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "getExtensionPrinters",
+      base::Bind(&PrintPreviewHandler::HandleGetExtensionPrinters,
+                 base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
+      "getExtensionPrinterCapabilities",
+      base::Bind(&PrintPreviewHandler::HandleGetExtensionPrinterCapabilities,
+                 base::Unretained(this)));
   RegisterForMergeSession();
 }
 
@@ -706,6 +718,42 @@ void PrintPreviewHandler::HandleGetPrivetPrinterCapabilities(
 #endif
 }
 
+void PrintPreviewHandler::HandleGetExtensionPrinters(
+    const base::ListValue* args) {
+#if defined(ENABLE_EXTENSIONS)
+  // TODO(tbarzic): Handle case where a new search is initiated before the
+  // previous one finishes. Currently, in this case Web UI layer may get
+  // multiple events with printer list from some extensions, and it may get
+  // fooled by |done| flag from the first search into marking the search
+  // complete.
+  extensions::PrinterProviderAPI::GetFactoryInstance()
+      ->Get(preview_web_contents()->GetBrowserContext())
+      ->DispatchGetPrintersRequested(
+          base::Bind(&PrintPreviewHandler::OnGotPrintersForExtension,
+                     weak_factory_.GetWeakPtr()));
+#else
+  OnGotPrintersForExtension(base::ListValue(), true /* done */);
+#endif
+}
+
+void PrintPreviewHandler::HandleGetExtensionPrinterCapabilities(
+    const base::ListValue* args) {
+  std::string printer_id;
+  bool ok = args->GetString(0, &printer_id);
+  DCHECK(ok);
+
+#if defined(ENABLE_EXTENSIONS)
+  extensions::PrinterProviderAPI::GetFactoryInstance()
+      ->Get(preview_web_contents()->GetBrowserContext())
+      ->DispatchGetCapabilityRequested(
+          printer_id,
+          base::Bind(&PrintPreviewHandler::OnGotExtensionPrinterCapabilities,
+                     weak_factory_.GetWeakPtr(), printer_id));
+#else
+  OnGotExtensionPrinterCapabilities(printer_id, base::DictionaryValue());
+#endif
+}
+
 void PrintPreviewHandler::HandleGetPreview(const base::ListValue* args) {
   DCHECK_EQ(3U, args->GetSize());
   scoped_ptr<base::DictionaryValue> settings(GetSettingsDictionary(args));
@@ -1588,6 +1636,26 @@ void PrintPreviewHandler::FillPrinterDescription(
 
 #endif  // defined(ENABLE_SERVICE_DISCOVERY)
 
+void PrintPreviewHandler::OnGotPrintersForExtension(
+    const base::ListValue& printers,
+    bool done) {
+  web_ui()->CallJavascriptFunction("onExtensionPrintersAdded", printers,
+                                   base::FundamentalValue(done));
+}
+
+void PrintPreviewHandler::OnGotExtensionPrinterCapabilities(
+    const std::string& printer_id,
+    const base::DictionaryValue& capabilities) {
+  if (capabilities.empty()) {
+    web_ui()->CallJavascriptFunction("failedToGetExtensionPrinterCapabilities",
+                                     base::StringValue(printer_id));
+    return;
+  }
+
+  web_ui()->CallJavascriptFunction("onExtensionCapabilitiesSet",
+                                   base::StringValue(printer_id), capabilities);
+}
+
 void PrintPreviewHandler::RegisterForMergeSession() {
   DCHECK(!reconcilor_);
   Profile* profile = Profile::FromWebUI(web_ui());