Handle an extension printer supporting only PWG raster data

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

Index: chrome/browser/ui/webui/print_preview/extension_printer_handler.cc
diff --git a/chrome/browser/ui/webui/print_preview/extension_printer_handler.cc b/chrome/browser/ui/webui/print_preview/extension_printer_handler.cc
index 4f032c87704de7027e234e2b21efe1641a1b0b95..ec36966f873fae4cbc8a8866eed6fe1041634153 100644
--- a/chrome/browser/ui/webui/print_preview/extension_printer_handler.cc
+++ b/chrome/browser/ui/webui/print_preview/extension_printer_handler.cc
@@ -4,21 +4,74 @@
 
 #include "chrome/browser/ui/webui/print_preview/extension_printer_handler.h"
 
+#include <algorithm>
+
 #include "base/bind.h"
 #include "base/callback.h"
-#include "base/values.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/location.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/single_thread_task_runner.h"
+#include "base/thread_task_runner_handle.h"
+#include "base/threading/worker_pool.h"
+#include "chrome/browser/local_discovery/pwg_raster_converter.h"
 #include "components/cloud_devices/common/cloud_device_description.h"
 #include "components/cloud_devices/common/printer_description.h"
 #include "extensions/browser/api/printer_provider/printer_provider_api.h"
-#include "printing/print_job_constants.h"
-
+#include "printing/pdf_render_settings.h"
+#include "printing/pwg_raster_settings.h"
+#include "printing/units.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/size.h"
 namespace {
 
 const char kContentTypePdf[] = "application/pdf";
+const char kContentTypePWGRaster[] = "image/pwg-raster";
 const char kContentTypeAll[] = "*/*";
 
 const char kInvalidDataPrintError[] = "INVALID_DATA";
 
+// Reads raster data from file path |raster_path| to a RefCountedMemory object,
+// which is then passed to |callback| on |response_task_runner|.
+void ReadConvertedPWGRasterFileOnWorkerThread(
+    const base::FilePath& raster_path,
+    const scoped_refptr<base::SingleThreadTaskRunner>& response_task_runner,
+    const ExtensionPrinterHandler::RefCountedMemoryCallback& callback) {
+  scoped_refptr<base::RefCountedMemory> result;
+  int64 file_size;
+  if (base::GetFileSize(raster_path, &file_size) &&
+      file_size <= extensions::PrinterProviderAPI::kMaxDocumentSize) {
+    scoped_ptr<std::string> data(new std::string());
+    data->reserve(file_size);
+
+    if (base::ReadFileToString(raster_path, data.get()))
+      result = base::RefCountedString::TakeString(data.release());
+  } else {
+    LOG(ERROR) << "Invalid raster file size.";
+  }
+
+  response_task_runner->PostTask(FROM_HERE, base::Bind(callback, result));
+}
+
+// Posts a task to read a file containing converted PWG raster data to the
+// worker pool.
+void ReadConvertedPWGRasterFile(
+    const ExtensionPrinterHandler::RefCountedMemoryCallback& callback,
+    bool success,
+    const base::FilePath& pwg_file_path) {
+  if (!success) {
+    callback.Run(scoped_refptr<base::RefCountedMemory>());
+    return;
+  }
+
+  base::WorkerPool::GetTaskRunner(true)->PostTask(

[Vitaly Buka (NO REVIEWS), 2015/02/17 19:43:54]

PostTaskAndReplyWithResult is appropriate here

[tbarzic, 2015/02/18 02:55:49]

Done.

+      FROM_HERE,
+      base::Bind(&ReadConvertedPWGRasterFileOnWorkerThread, pwg_file_path,
+                 base::ThreadTaskRunnerHandle::Get(), callback));
+}
+
 }  // namespace
 
 ExtensionPrinterHandler::ExtensionPrinterHandler(
@@ -59,11 +112,13 @@ void ExtensionPrinterHandler::StartPrint(
     const std::string& destination_id,
     const std::string& capability,
     const std::string& ticket_json,
+    const gfx::Size& size,
     const scoped_refptr<base::RefCountedMemory>& print_data,
     const PrinterHandler::PrintCallback& callback) {
-  extensions::PrinterProviderAPI::PrintJob print_job;
-  print_job.printer_id = destination_id;
-  print_job.ticket_json = ticket_json;
+  scoped_ptr<extensions::PrinterProviderAPI::PrintJob> print_job(
+      new extensions::PrinterProviderAPI::PrintJob());
+  print_job->printer_id = destination_id;
+  print_job->ticket_json = ticket_json;
 
   cloud_devices::CloudDeviceDescription printer_description;
   printer_description.InitFromString(capability);
@@ -74,20 +129,63 @@ void ExtensionPrinterHandler::StartPrint(
   const bool kUsePdf = content_types.Contains(kContentTypePdf) ||
                        content_types.Contains(kContentTypeAll);
 
-  if (!kUsePdf) {
-    // TODO(tbarzic): Convert data to PWG raster if the printer does not support
-    // PDF.
+  if (kUsePdf) {
+    print_job->content_type = kContentTypePdf;
+    DispatchPrintJob(callback, print_job.Pass(), print_data);
+    return;
+  }
+
+  print_job->content_type = kContentTypePWGRaster;
+  ConvertToPWGRaster(print_data, printer_description, size,
+                     base::Bind(&ExtensionPrinterHandler::DispatchPrintJob,
+                                weak_ptr_factory_.GetWeakPtr(), callback,
+                                base::Passed(&print_job)));
+}
+
+void ExtensionPrinterHandler::ConvertToPWGRaster(
+    const scoped_refptr<base::RefCountedMemory>& data,
+    const cloud_devices::CloudDeviceDescription& printer_description,
+    const gfx::Size& size,

[Vitaly Buka (NO REVIEWS), 2015/02/17 19:43:54]

looks like this code is very similar to privet version. Can we avoid code
duplication here?

[tbarzic, 2015/02/18 02:55:49]

Yeah, meant to do that before sending the cl for review, but forgot about it.
Also, I'm missing piece that fills out PwgRasterSettings passed to the
converter.

Moved this part to a separate cl:
https://codereview.chromium.org/935673004/

+    const ExtensionPrinterHandler::RefCountedMemoryCallback& callback) {
+
+  int dpi = printing::kDefaultPdfDpi;
+  cloud_devices::printer::DpiCapability dpis;
+  if (dpis.LoadFrom(printer_description))
+    dpi = std::max(dpis.GetDefault().horizontal, dpis.GetDefault().vertical);
+
+  double scale = dpi;
+  scale /= printing::kPointsPerInch;
+
+  gfx::Rect area(std::min(size.width(), size.height()) * scale,
+                 std::max(size.width(), size.height()) * scale);
+
+  if (!pwg_raster_converter_) {
+    pwg_raster_converter_ =
+        local_discovery::PWGRasterConverter::CreateDefault();
+  }
+  pwg_raster_converter_->Start(
+      data.get(), printing::PdfRenderSettings(area, dpi, true),
+      printing::PwgRasterSettings(),
+      base::Bind(&ReadConvertedPWGRasterFile, callback));
+
+}
+
+void ExtensionPrinterHandler::DispatchPrintJob(
+    const PrinterHandler::PrintCallback& callback,
+    scoped_ptr<extensions::PrinterProviderAPI::PrintJob> print_job,
+    const scoped_refptr<base::RefCountedMemory>& print_data) {
+  if (!print_data) {
     WrapPrintCallback(callback, false, kInvalidDataPrintError);
     return;
   }
 
-  print_job.content_type = kContentTypePdf;
-  print_job.document_bytes = print_data;
+  print_job->document_bytes = print_data;
+
   extensions::PrinterProviderAPI::GetFactoryInstance()
       ->Get(browser_context_)
       ->DispatchPrintRequested(
-          print_job, base::Bind(&ExtensionPrinterHandler::WrapPrintCallback,
-                                weak_ptr_factory_.GetWeakPtr(), callback));
+          *print_job, base::Bind(&ExtensionPrinterHandler::WrapPrintCallback,
+                                 weak_ptr_factory_.GetWeakPtr(), callback));
 }
 
 void ExtensionPrinterHandler::WrapGetPrintersCallback(