Handle RGB video correctly.

Turns out that when a video is tagged as RGB,
they really mean that the Y channel contains green,
Cr contains red, and Cb contains blue.
(According to ISO 23001-8:2016)

Bug: 901664
Change-Id: I468327252389dc2468020f23a912129fdc55574a
Reviewed-on: https://chromium-review.googlesource.com/c/1321582Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Fredrik Hubinette <hubbe@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607442}

media/base/video_color_space.cc

@@ -188,7 +188,9 @@ gfx::ColorSpace VideoColorSpace::ToGfxColorSpace() const {
 
   switch (matrix) {
     case MatrixID::RGB:
-      matrix_id = gfx::ColorSpace::MatrixID::RGB;
+      // RGB-encoded video actually puts the green in the Y channel,
+      // the blue in the Cb (U) channel and the red in the Cr (V) channel.
+      matrix_id = gfx::ColorSpace::MatrixID::GBR;
       break;
     case MatrixID::BT709:
       matrix_id = gfx::ColorSpace::MatrixID::BT709;

ui/gfx/color_space.cc

@@ -375,6 +375,7 @@ std::string ColorSpace::ToString() const {
     PRINT_ENUM_CASE(MatrixID, BT2020_NCL)
     PRINT_ENUM_CASE(MatrixID, BT2020_CL)
     PRINT_ENUM_CASE(MatrixID, YDZDX)
+    PRINT_ENUM_CASE(MatrixID, GBR)
   }
   ss << ", range:";
   switch (range_) {
@@ -883,6 +884,14 @@ void ColorSpace::GetTransferMatrix(SkMatrix44* matrix) const {
       matrix->setRowMajorf(data);
       return;
     }
+    case ColorSpace::MatrixID::GBR: {
+      float data[16] = {0.0f, 1.0f, 0.0f, 0.0f,  // G
+                        0.0f, 0.0f, 1.0f, 0.0f,  // B
+                        1.0f, 0.0f, 0.0f, 0.0f,  // R
+                        0.0f, 0.0f, 0.0f, 1.0f};
+      matrix->setRowMajorf(data);
+      return;
+    }
   }
   float Kg = 1.0f - Kr - Kb;
   float u_m = 0.5f / (1.0f - Kb);
@@ -909,6 +918,7 @@ void ColorSpace::GetRangeAdjustMatrix(SkMatrix44* matrix) const {
   }
   switch (matrix_) {
     case MatrixID::RGB:
+    case MatrixID::GBR:
     case MatrixID::INVALID:
     case MatrixID::YCOCG:
       matrix->setScale(255.0f/219.0f, 255.0f/219.0f, 255.0f/219.0f);

ui/gfx/color_space.h

@@ -105,7 +105,8 @@ class COLOR_SPACE_EXPORT ColorSpace {
     BT2020_NCL,
     BT2020_CL,
     YDZDX,
-    LAST = YDZDX,
+    GBR,
+    LAST = GBR,
   };
 
   enum class RangeID : uint8_t {

ui/gfx/color_space_win.cc

@@ -44,6 +44,7 @@ DXVA2_ExtendedFormat ColorSpaceWin::GetExtendedFormat(
       break;
 
     case gfx::ColorSpace::MatrixID::RGB:
+    case gfx::ColorSpace::MatrixID::GBR:
     case gfx::ColorSpace::MatrixID::FCC:
     case gfx::ColorSpace::MatrixID::YCOCG:
     case gfx::ColorSpace::MatrixID::BT2020_NCL:
@@ -226,6 +227,7 @@ D3D11_VIDEO_PROCESSOR_COLOR_SPACE ColorSpaceWin::GetD3D11ColorSpace(
 
     case gfx::ColorSpace::MatrixID::SMPTE240M:
     case gfx::ColorSpace::MatrixID::RGB:
+    case gfx::ColorSpace::MatrixID::GBR:
     case gfx::ColorSpace::MatrixID::FCC:
     case gfx::ColorSpace::MatrixID::YCOCG:
     case gfx::ColorSpace::MatrixID::BT2020_NCL: