Add conversion from pp::ImageData to SkBitmap

Adds a new function, SkBitmapFromPPImageData(), that converts from
pp::ImageData to SkBitmap. SkBitmap can then be used to replace any
instances of pp::ImageData. Note that the underlying pixel memory is
shared, so these conversions are relatively cheap.

As an example, converts chrome_pdf::draw_utils::DrawShadow() to accept
an SkBitmap& instead of a pp::ImageData*.

Bug: 1099020
Change-Id: Ib5ed84fe45f2a4ac882ba6b367a02398ba256c5f
Cq-Do-Not-Cancel-Tryjobs: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2270813
Reviewed-by: Dirk Pranke <dpranke@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Daniel Hosseinian <dhoss@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: K. Moon <kmoon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#787942}

pdf/BUILD.gn

@@ -57,6 +57,8 @@ if (enable_pdf) {
       "pdf_ppapi.cc",
       "pdf_transform.cc",
       "pdf_transform.h",
+      "ppapi_migration/bitmap.cc",
+      "ppapi_migration/bitmap.h",
       "ppapi_migration/callback.cc",
       "ppapi_migration/callback.h",
       "ppapi_migration/geometry_conversions.cc",
@@ -91,6 +93,7 @@ if (enable_pdf) {
       "//net",
       "//ppapi/cpp:objects",
       "//ppapi/cpp/private:internal_module",
+      "//skia",
       "//ui/base",
       "//ui/gfx/range",
     ]

pdf/DEPS

@@ -2,6 +2,7 @@ include_rules = [
   "+net",
   "+ppapi",
   "+printing/units.h",
+  "+third_party/skia/include/core",
   "+ui/base/window_open_disposition.h",
   "+ui/events/keycodes/keyboard_codes.h",
   "+ui/gfx/geometry",

pdf/draw_utils/shadow.cc

@@ -10,8 +10,8 @@
 #include <algorithm>
 
 #include "base/check_op.h"
-#include "ppapi/cpp/image_data.h"
 #include "ppapi/cpp/rect.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 
 namespace chrome_pdf {
 namespace draw_utils {
@@ -110,7 +110,7 @@ ShadowMatrix::~ShadowMatrix() = default;
 
 namespace {
 
-void PaintShadow(pp::ImageData* image,
+void PaintShadow(SkBitmap& image,
                  const pp::Rect& clip_rc,
                  const pp::Rect& shadow_rc,
                  const ShadowMatrix& matrix) {
@@ -125,7 +125,7 @@ void PaintShadow(pp::ImageData* image,
                                   depth - shadow_rc.right() + x);
       int32_t matrix_y = std::max(depth + shadow_rc.y() - y - 1,
                                   depth - shadow_rc.bottom() + y);
-      uint32_t* pixel = image->GetAddr32(pp::Point(x, y));
+      uint32_t* pixel = image.getAddr32(x, y);
 
       if (matrix_x < 0)
         matrix_x = 0;
@@ -144,7 +144,7 @@ void PaintShadow(pp::ImageData* image,
 
 }  // namespace
 
-void DrawShadow(pp::ImageData* image,
+void DrawShadow(SkBitmap& image,
                 const pp::Rect& shadow_rc,
                 const pp::Rect& object_rc,
                 const pp::Rect& clip_rc,

pdf/draw_utils/shadow.h

@@ -9,8 +9,9 @@
 
 #include <vector>
 
+class SkBitmap;
+
 namespace pp {
-class ImageData;
 class Rect;
 }  // namespace pp
 
@@ -46,7 +47,7 @@ class ShadowMatrix {
 // shadow_rc - rectangle occupied by shadow
 // object_rc - rectangle that drops the shadow
 // clip_rc - clipping region
-void DrawShadow(pp::ImageData* image,
+void DrawShadow(SkBitmap& image,
                 const pp::Rect& shadow_rc,
                 const pp::Rect& object_rc,
                 const pp::Rect& clip_rc,

pdf/pdfium/pdfium_engine.cc

@@ -41,6 +41,7 @@
 #include "pdf/pdfium/pdfium_mem_buffer_file_write.h"
 #include "pdf/pdfium/pdfium_permissions.h"
 #include "pdf/pdfium/pdfium_unsupported_features.h"
+#include "pdf/ppapi_migration/bitmap.h"
 #include "pdf/ppapi_migration/input_event_conversions.h"
 #include "pdf/url_loader_wrapper_impl.h"
 #include "ppapi/c/ppb_input_event.h"
@@ -56,6 +57,7 @@
 #include "third_party/pdfium/public/fpdf_fwlevent.h"
 #include "third_party/pdfium/public/fpdf_ppo.h"
 #include "third_party/pdfium/public/fpdf_searchex.h"
+#include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/gfx/geometry/rect.h"
 #include "v8/include/v8.h"
@@ -3501,8 +3503,12 @@ void PDFiumEngine::DrawPageShadow(const pp::Rect& page_rc,
         depth, factor, client_->GetBackgroundColor());
   }
 
+  // TODO(crbug.com/1099020): Converting to SkBitmap here may seem silly, but
+  // this is part of a migration from pp::ImageData to SkBitmap in general.
   DCHECK(!image_data->is_null());
-  DrawShadow(image_data, shadow_rect, page_rect, clip_rect, *page_shadow_);
+  SkBitmap bitmap =
+      SkBitmapFromPPImageData(std::make_unique<pp::ImageData>(*image_data));
+  DrawShadow(bitmap, shadow_rect, page_rect, clip_rect, *page_shadow_);
 }
 
 void PDFiumEngine::GetRegion(const pp::Point& location,

pdf/ppapi_migration/bitmap.cc

@@ -0,0 +1,51 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "pdf/ppapi_migration/bitmap.h"
+
+#include <stdint.h>
+
+#include <memory>
+
+#include "base/check_op.h"
+#include "ppapi/cpp/image_data.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/skia/include/core/SkImageInfo.h"
+
+namespace chrome_pdf {
+
+namespace {
+
+// Releases pp::ImageData associated with the SkPixelRef. The pp::ImageData acts
+// like a shared pointer to memory provided by Pepper, and must be retained for
+// the life of the SkPixelRef.
+void ReleaseImageData(void* addr, void* context) {
+  pp::ImageData* image_data = static_cast<pp::ImageData*>(context);
+  DCHECK_EQ(addr, image_data->data());
+  delete image_data;
+}
+
+}  // namespace
+
+SkBitmap SkBitmapFromPPImageData(std::unique_ptr<pp::ImageData> image_data) {
+  if (image_data->is_null()) {
+    return SkBitmap();
+  }
+
+  // Note that we unconditionally use BGRA_PREMUL with PDFium.
+  DCHECK_EQ(image_data->format(), PP_IMAGEDATAFORMAT_BGRA_PREMUL);
+  SkImageInfo info =
+      SkImageInfo::Make(image_data->size().width(), image_data->size().height(),
+                        kBGRA_8888_SkColorType, kPremul_SkAlphaType);
+  void* data = image_data->data();
+  int32_t stride = image_data->stride();
+
+  SkBitmap bitmap;
+  bool success = bitmap.installPixels(info, data, stride, ReleaseImageData,
+                                      image_data.release());
+  DCHECK(success);
+  return bitmap;
+}
+
+}  // namespace chrome_pdf

pdf/ppapi_migration/bitmap.h

@@ -0,0 +1,30 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PDF_PPAPI_MIGRATION_BITMAP_H_
+#define PDF_PPAPI_MIGRATION_BITMAP_H_
+
+#include <memory>
+
+class SkBitmap;
+
+namespace pp {
+class ImageData;
+}  // namespace pp
+
+namespace chrome_pdf {
+
+// Creates an SkBitmap from a pp::ImageData. The SkBitmap takes ownership of the
+// pp::ImageData, and shares ownership of the underlying pixel memory. (Note
+// that it's easy to make a shallow copy of a pp::ImageData.)
+//
+// In case of an error, returns an empty SkBitmap.
+//
+// TODO(kmoon): Skia is trying to get rid of SkBitmap in favor of immutable
+// types like SkImage, so we should migrate once PDFium is ready for Skia.
+SkBitmap SkBitmapFromPPImageData(std::unique_ptr<pp::ImageData> image_data);
+
+}  // namespace chrome_pdf
+
+#endif  // PDF_PPAPI_MIGRATION_BITMAP_H_