ImageCapture: Implement takePhoto() for Windows

media/capture/video/blob_utils.cc

+// Copyright 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 "media/capture/video/blob_utils.h"
+

[xianglu, 2016/09/20 18:43:03]

nit: redundant line

[mcasas, 2016/09/20 19:51:10]

?
l.5 needs to be separated [1], and I should
include both l.7 and l.8: "If you rely on 
symbols from bar.h, don't count on the fact 
that you included foo.h which (currently) 
includes bar.h: include bar.h yourself" ([1]).

[1]
https://google.github.io/styleguide/cppguide.html#Names_and_Order_of_Includes

[xianglu, 2016/09/20 20:42:58]

I thought l.6 was redundant.

+#include "media/base/video_capture_types.h"
+#include "media/base/video_frame.h"
+#include "third_party/libyuv/include/libyuv.h"
+#include "third_party/skia/include/core/SkImage.h"
+#include "ui/gfx/codec/png_codec.h"
+
+namespace media {
+
+mojom::BlobPtr Blobify(const uint8_t* buffer,
+                       const uint32_t bytesused,
+                       VideoCaptureFormat capture_format) {
+  DCHECK(buffer);
+  DCHECK(bytesused);
+  DCHECK(capture_format.IsValid());
+
+  const VideoPixelFormat pixel_format = capture_format.pixel_format;
+  if (pixel_format == VideoPixelFormat::PIXEL_FORMAT_MJPEG) {
+    mojom::BlobPtr blob = mojom::Blob::New();
+    blob->data.resize(bytesused);
+    memcpy(blob->data.data(), buffer, bytesused);
+    blob->mime_type = "image/jpeg";
+    return blob;
+  }
+
+  uint32_t src_format;
+  if (pixel_format == VideoPixelFormat::PIXEL_FORMAT_UYVY)
+    src_format = libyuv::FOURCC_UYVY;
+  else if (pixel_format == VideoPixelFormat::PIXEL_FORMAT_YUY2)
+    src_format = libyuv::FOURCC_YUY2;
+  else if (pixel_format == VideoPixelFormat::PIXEL_FORMAT_I420)
+    src_format = libyuv::FOURCC_I420;
+  else if (pixel_format == VideoPixelFormat::PIXEL_FORMAT_RGB24)
+    src_format = libyuv::FOURCC_24BG;
+  else
+    return nullptr;
+
+  // PNGCodec does not support YUV formats, convert to a temporary ARGB buffer.
+  std::unique_ptr<uint8_t[]> tmp_argb(new uint8_t[VideoFrame::AllocationSize(

[xianglu, 2016/09/20 18:43:03]

Since it's used several times below, maybe you can factor out this too:
const gfx::Size frame_size = capture_format.frame_size;

[mcasas, 2016/09/20 19:51:10]

Done.

+      PIXEL_FORMAT_ARGB, capture_format.frame_size)]);
+  if (ConvertToARGB(buffer, bytesused, tmp_argb.get(),
+                    capture_format.frame_size.width() * 4, 0 /* crop_x_pos */,
+                    0 /* crop_y_pos */, capture_format.frame_size.width(),
+                    capture_format.frame_size.height(),
+                    capture_format.frame_size.width(),
+                    capture_format.frame_size.height(),
+                    libyuv::RotationMode::kRotate0, src_format) != 0) {
+    return nullptr;
+  }
+
+  mojom::BlobPtr blob = mojom::Blob::New();
+  const gfx::PNGCodec::ColorFormat codec_color_format =
+      (kN32_SkColorType == kRGBA_8888_SkColorType) ? gfx::PNGCodec::FORMAT_RGBA
+                                                   : gfx::PNGCodec::FORMAT_BGRA;
+  const bool result = gfx::PNGCodec::Encode(
+      tmp_argb.get(), codec_color_format, capture_format.frame_size,
+      capture_format.frame_size.width() * 4, true /* discard_transparency */,
+      std::vector<gfx::PNGCodec::Comment>(), &blob->data);
+  DCHECK(result);
+
+  blob->mime_type = "image/png";
+  return blob;
+}
+
+}  // namespace media