Implement SkEncodeImage()

This change replaces the implementation in SkImageEncoder_none.cpp with
an implementation that allows the layer above to define an image
encoding function.

Background:  Skia's (experimental) XPS backend needs a PNG encoder.
Skia for Chromium does not compile its PNG encoder, but there is one
available in Chrome's gfx component.  To make layering work right,
I allow the layer above skia (gfx) to define an encoding function
that can be installed into skia.

TODO: initialize the function pointer in printing process.

Also: Revert "SK_SUPPORT_LEGACY_IMAGE_ENCODER_CLASS"
This reverts commit 1430e85b.

BUG=chromium:616763

Review-Url: https://codereview.chromium.org/2527833002
Cr-Commit-Position: refs/heads/master@{#441395}

skia/BUILD.gn

@@ -207,6 +207,8 @@ component("skia") {
     "ext/opacity_filter_canvas.cc",
     "ext/platform_device.cc",
     "ext/recursive_gaussian_convolution.cc",
+    "ext/skia_encode_image.cc",
+    "ext/skia_encode_image.h",
     "ext/skia_histogram.cc",
     "ext/skia_memory_dump_provider.cc",
     "ext/skia_trace_memory_dump_impl.cc",
@@ -247,7 +249,6 @@ component("skia") {
     "//third_party/skia/src/ports/SkFontMgr_android_parser.cpp",
     "//third_party/skia/src/ports/SkFontMgr_win_dw.cpp",
     "//third_party/skia/src/ports/SkGlobalInitialization_default.cpp",
-    "//third_party/skia/src/ports/SkImageEncoder_none.cpp",
     "//third_party/skia/src/ports/SkImageGenerator_none.cpp",
     "//third_party/skia/src/ports/SkOSFile_posix.cpp",
     "//third_party/skia/src/ports/SkOSFile_stdio.cpp",

skia/config/SkUserConfig.h

@@ -220,10 +220,6 @@ SK_API void SkDebugf_FileLine(const char* file, int line, bool fatal,
 #   define SK_DISABLE_COLOR_XFORM_PIPELINE
 #endif
 
-#ifndef    SK_SUPPORT_LEGACY_IMAGE_ENCODER_CLASS
-#   define SK_SUPPORT_LEGACY_IMAGE_ENCODER_CLASS
-#endif
-
 #ifndef    SK_SUPPORT_LEGACY_BITMAP_SETPIXELREF
 #   define SK_SUPPORT_LEGACY_BITMAP_SETPIXELREF
 #endif

skia/ext/skia_encode_image.cc

+// Copyright (c) 2016 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 "skia/ext/skia_encode_image.h"
+
+#include "third_party/skia/include/core/SkImageEncoder.h"
+
+static skia::ImageEncoderFunction g_image_encoder = nullptr;
+
+void skia::SetImageEncoder(skia::ImageEncoderFunction image_encoder) {
+  g_image_encoder = image_encoder;
+}
+
+bool SkEncodeImage(SkWStream* stream,
+                   const SkPixmap& pixmap,
+                   SkEncodedImageFormat format,
+                   int quality) {
+  skia::ImageEncoderFunction encoder = g_image_encoder;
+  return encoder && encoder(stream, pixmap, format, quality);
+}

skia/ext/skia_encode_image.h

+// Copyright (c) 2016 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 SKIA_EXT_SKIA_ENCODE_IMAGE_H
+#define SKIA_EXT_SKIA_ENCODE_IMAGE_H
+
+#include "third_party/skia/include/core/SkEncodedImageFormat.h"
+#include "third_party/skia/include/core/SkTypes.h"
+
+class SkPixmap;
+class SkWStream;
+
+namespace skia {
+
+using ImageEncoderFunction = bool (*)(SkWStream*,
+                                      const SkPixmap&,
+                                      SkEncodedImageFormat,
+                                      int quality);
+
+SK_API void SetImageEncoder(ImageEncoderFunction);
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_SKIA_ENCODE_IMAGE_H

ui/gfx/BUILD.gn

@@ -57,6 +57,8 @@ component("gfx") {
     "codec/jpeg_codec.h",
     "codec/png_codec.cc",
     "codec/png_codec.h",
+    "codec/skia_image_encoder_adapter.cc",
+    "codec/skia_image_encoder_adapter.h",
     "color_analysis.cc",
     "color_analysis.h",
     "color_palette.h",

ui/gfx/codec/skia_image_encoder_adapter.cc

+// Copyright (c) 2016 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 "ui/gfx/codec/skia_image_encoder_adapter.h"
+
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "third_party/skia/include/core/SkStream.h"
+#include "ui/gfx/codec/jpeg_codec.h"
+#include "ui/gfx/codec/png_codec.h"
+#include "ui/gfx/geometry/size.h"
+
+bool gfx::EncodeSkiaImage(SkWStream* dst,
+                          const SkPixmap& pixmap,
+                          SkEncodedImageFormat format,
+                          int quality) {
+  if (kN32_SkColorType != pixmap.colorType() ||
+      (kPremul_SkAlphaType != pixmap.alphaType() &&
+       kOpaque_SkAlphaType != pixmap.alphaType())) {
+    return false;
+  }
+  std::vector<unsigned char> buffer;
+  switch (format) {
+    case SkEncodedImageFormat::kPNG:
+      return gfx::PNGCodec::Encode(
+                 reinterpret_cast<const unsigned char*>(pixmap.addr()),
+                 gfx::PNGCodec::FORMAT_SkBitmap,
+                 gfx::Size(pixmap.width(), pixmap.height()),
+                 static_cast<int>(pixmap.rowBytes()), false,
+                 std::vector<gfx::PNGCodec::Comment>(), &buffer) &&
+             dst->write(buffer.data(), buffer.size());
+    case SkEncodedImageFormat::kJPEG:
+      return gfx::JPEGCodec::Encode(
+                 reinterpret_cast<const unsigned char*>(pixmap.addr()),
+                 gfx::JPEGCodec::FORMAT_SkBitmap, pixmap.width(),
+                 pixmap.height(), static_cast<int>(pixmap.rowBytes()), quality,
+                 &buffer) &&
+             dst->write(buffer.data(), buffer.size());
+    default:
+      return false;
+  }
+}

ui/gfx/codec/skia_image_encoder_adapter.h

+// Copyright (c) 2016 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 UI_GFX_CODEC_SKIA_IMAGE_ENCODER_ADAPTER_H
+#define UI_GFX_CODEC_SKIA_IMAGE_ENCODER_ADAPTER_H
+
+#include "third_party/skia/include/core/SkEncodedImageFormat.h"
+#include "ui/gfx/gfx_export.h"
+
+class SkWStream;
+class SkPixmap;
+
+namespace gfx {
+
+// Matches signature of Skia's SkEncodeImage, but makes use of Chromium's
+// encoders.
+GFX_EXPORT bool EncodeSkiaImage(SkWStream* dst,
+                                const SkPixmap& pixmap,
+                                SkEncodedImageFormat format,
+                                int quality);
+
+}  // namespace gfx
+
+#endif  // UI_GFX_CODEC_SKIA_IMAGE_ENCODER_ADAPTER_H