Printing: Add metrics for PDF to PWG Raster conversions.

BUG=792308

Change-Id: I151965cc99c4bd757176c3af87971e28f6c347da
Reviewed-on: https://chromium-review.googlesource.com/1069560Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Jay Civelli <jcivelli@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561599}

chrome/browser/printing/cloud_print/privet_http_unittest.cc

@@ -776,7 +776,7 @@ TEST_P(PrivetCapabilitiesTest, BadToken) {
 // request is uploading a file that is based on this pattern.
 class FakePwgRasterConverter : public printing::PwgRasterConverter {
  public:
-  void Start(base::RefCountedMemory* data,
+  void Start(const base::RefCountedMemory* data,
              const printing::PdfRenderSettings& conversion_settings,
              const printing::PwgRasterSettings& bitmap_settings,
              ResultCallback callback) override {

chrome/browser/printing/pwg_raster_converter.cc

@@ -12,6 +12,7 @@
 #include "base/cancelable_callback.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/metrics/histogram_macros.h"
 #include "chrome/services/printing/public/mojom/constants.mojom.h"
 #include "chrome/services/printing/public/mojom/pdf_to_pwg_raster_converter.mojom.h"
 #include "components/cloud_devices/common/cloud_device_description.h"
@@ -40,7 +41,7 @@ class PwgRasterConverterHelper
   PwgRasterConverterHelper(const PdfRenderSettings& settings,
                            const PwgRasterSettings& bitmap_settings);
 
-  void Convert(base::RefCountedMemory* data,
+  void Convert(const base::RefCountedMemory* data,
                PwgRasterConverter::ResultCallback callback);
 
  private:
@@ -48,7 +49,8 @@ class PwgRasterConverterHelper
 
   ~PwgRasterConverterHelper();
 
-  void RunCallback(base::ReadOnlySharedMemoryRegion region);
+  void RunCallback(base::ReadOnlySharedMemoryRegion region,
+                   uint32_t page_count);
 
   PdfRenderSettings settings_;
   PwgRasterSettings bitmap_settings_;
@@ -71,7 +73,7 @@ PwgRasterConverterHelper::~PwgRasterConverterHelper() {
 }
 
 void PwgRasterConverterHelper::Convert(
-    base::RefCountedMemory* data,
+    const base::RefCountedMemory* data,
     PwgRasterConverter::ResultCallback callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
@@ -84,12 +86,12 @@ void PwgRasterConverterHelper::Convert(
 
   pdf_to_pwg_raster_converter_ptr_.set_connection_error_handler(
       base::BindOnce(&PwgRasterConverterHelper::RunCallback, this,
-                     base::ReadOnlySharedMemoryRegion()));
+                     base::ReadOnlySharedMemoryRegion(), /*page_count=*/0));
 
   base::MappedReadOnlyRegion memory =
       base::ReadOnlySharedMemoryRegion::Create(data->size());
   if (!memory.IsValid()) {
-    RunCallback(base::ReadOnlySharedMemoryRegion());
+    RunCallback(base::ReadOnlySharedMemoryRegion(), /*page_count=*/0);
     return;
   }
 
@@ -102,10 +104,21 @@ void PwgRasterConverterHelper::Convert(
 }
 
 void PwgRasterConverterHelper::RunCallback(
-    base::ReadOnlySharedMemoryRegion region) {
+    base::ReadOnlySharedMemoryRegion region,
+    uint32_t page_count) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (callback_)
+  if (callback_) {
+    if (region.IsValid() && page_count > 0) {
+      size_t average_page_size_in_kb = region.GetSize() / 1024;
+      average_page_size_in_kb /= page_count;
+      UMA_HISTOGRAM_MEMORY_KB("Printing.ConversionSize.Pwg",
+                              average_page_size_in_kb);
       std::move(callback_).Run(std::move(region));
+    } else {
+      // TODO(thestig): Consider adding UMA to track failure rates.
+      std::move(callback_).Run(base::ReadOnlySharedMemoryRegion());
+    }
+  }
   pdf_to_pwg_raster_converter_ptr_.reset();
 }
 
@@ -114,7 +127,7 @@ class PwgRasterConverterImpl : public PwgRasterConverter {
   PwgRasterConverterImpl();
   ~PwgRasterConverterImpl() override;
 
-  void Start(base::RefCountedMemory* data,
+  void Start(const base::RefCountedMemory* data,
              const PdfRenderSettings& conversion_settings,
              const PwgRasterSettings& bitmap_settings,
              ResultCallback callback) override;
@@ -122,9 +135,9 @@ class PwgRasterConverterImpl : public PwgRasterConverter {
  private:
   scoped_refptr<PwgRasterConverterHelper> utility_client_;
 
-  // Cancelable version of ResultCallback.
+  // Cancelable version of PwgRasterConverter::ResultCallback.
   base::CancelableOnceCallback<void(base::ReadOnlySharedMemoryRegion)>
-      callback_;
+      cancelable_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(PwgRasterConverterImpl);
 };
@@ -133,14 +146,14 @@ PwgRasterConverterImpl::PwgRasterConverterImpl() = default;
 
 PwgRasterConverterImpl::~PwgRasterConverterImpl() = default;
 
-void PwgRasterConverterImpl::Start(base::RefCountedMemory* data,
+void PwgRasterConverterImpl::Start(const base::RefCountedMemory* data,
                                    const PdfRenderSettings& conversion_settings,
                                    const PwgRasterSettings& bitmap_settings,
                                    ResultCallback callback) {
-  callback_.Reset(std::move(callback));
+  cancelable_callback_.Reset(std::move(callback));
   utility_client_ = base::MakeRefCounted<PwgRasterConverterHelper>(
       conversion_settings, bitmap_settings);
-  utility_client_->Convert(data, callback_.callback());
+  utility_client_->Convert(data, cancelable_callback_.callback());
 }
 
 }  // namespace

chrome/browser/printing/pwg_raster_converter.h

@@ -49,7 +49,7 @@ class PwgRasterConverter {
       const cloud_devices::CloudDeviceDescription& printer_capabilities,
       const cloud_devices::CloudDeviceDescription& ticket);
 
-  virtual void Start(base::RefCountedMemory* data,
+  virtual void Start(const base::RefCountedMemory* data,
                      const PdfRenderSettings& conversion_settings,
                      const PwgRasterSettings& bitmap_settings,
                      ResultCallback callback) = 0;

chrome/browser/printing/pwg_raster_converter_browsertest.cc

@@ -80,7 +80,7 @@ class PdfToPwgRasterBrowserTest : public InProcessBrowserTest {
       : converter_(PwgRasterConverter::CreateDefault()) {}
   ~PdfToPwgRasterBrowserTest() override {}
 
-  void Convert(base::RefCountedMemory* pdf_data,
+  void Convert(const base::RefCountedMemory* pdf_data,
                const PdfRenderSettings& conversion_settings,
                const PwgRasterSettings& bitmap_settings,
                bool expect_success,

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

@@ -281,7 +281,7 @@ class FakePwgRasterConverter : public PwgRasterConverter {
 
   // PwgRasterConverter implementation. It writes |data| to shared memory.
   // Also, remembers conversion and bitmap settings passed into the method.
-  void Start(base::RefCountedMemory* data,
+  void Start(const base::RefCountedMemory* data,
              const printing::PdfRenderSettings& conversion_settings,
              const printing::PwgRasterSettings& bitmap_settings,
              ResultCallback callback) override {

chrome/services/printing/pdf_to_pwg_raster_converter.cc

@@ -22,7 +22,8 @@ namespace {
 base::ReadOnlySharedMemoryRegion RenderPdfPagesToPwgRaster(
     base::ReadOnlySharedMemoryRegion pdf_region,
     const PdfRenderSettings& settings,
-    const PwgRasterSettings& bitmap_settings) {
+    const PwgRasterSettings& bitmap_settings,
+    uint32_t* page_count) {
   base::ReadOnlySharedMemoryRegion invalid_pwg_region;
   base::ReadOnlySharedMemoryMapping pdf_mapping = pdf_region.Map();
   if (!pdf_mapping.IsValid())
@@ -101,6 +102,7 @@ base::ReadOnlySharedMemoryRegion RenderPdfPagesToPwgRaster(
   if (!region_mapping.IsValid())
     return invalid_pwg_region;
 
+  *page_count = total_page_count;
   memcpy(region_mapping.mapping.memory(), pwg_data.data(), pwg_data.size());
   return std::move(region_mapping.region);
 }
@@ -118,8 +120,10 @@ void PdfToPwgRasterConverter::Convert(
     const PdfRenderSettings& pdf_settings,
     const PwgRasterSettings& pwg_raster_settings,
     ConvertCallback callback) {
-  std::move(callback).Run(RenderPdfPagesToPwgRaster(
-      std::move(pdf_region), pdf_settings, pwg_raster_settings));
+  uint32_t page_count = 0;
+  base::ReadOnlySharedMemoryRegion region = RenderPdfPagesToPwgRaster(
+      std::move(pdf_region), pdf_settings, pwg_raster_settings, &page_count);
+  std::move(callback).Run(std::move(region), page_count);
 }
 
 }  // namespace printing

chrome/services/printing/public/mojom/pdf_to_pwg_raster_converter.mojom

@@ -32,5 +32,6 @@ interface PdfToPwgRasterConverter {
   Convert(mojo_base.mojom.ReadOnlySharedMemoryRegion pdf_region,
           PdfRenderSettings pdf_settings,
           PwgRasterSettings pwg_raster_settings)
-      => (mojo_base.mojom.ReadOnlySharedMemoryRegion? pwg_raster_region);
+      => (mojo_base.mojom.ReadOnlySharedMemoryRegion? pwg_raster_region,
+          uint32 page_count);
 };

tools/metrics/histograms/histograms.xml

@@ -73411,6 +73411,14 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="Printing.ConversionSize.Pwg" units="KB">
+  <owner>thestig@chromium.org</owner>
+  <summary>
+    On desktop, the average size of a printed page after converting to PWG
+    Raster format.
+  </summary>
+</histogram>
+
 <histogram name="Printing.CUPS.AddressResolutionResult" enum="BooleanSuccess">
   <owner>skau@chromium.org</owner>
   <summary>