We started redesigning GpuMemoryBuffer interface to handle multiple buffers [0][1].

[0] https://codereview.chromium.org/1024113003
[1] https://codereview.chromium.org/1062853002

In this CL:

- I added new format GL_RGB_YUV_420_CHROMIUM
- I edited gpu/GLES2/extensions/CHROMIUM/CHROMIUM_*.txt files to include these new tokens.

The future steps are:
- Implement support for YUV_420 in GpuMemoryBufferFactoryOzoneNativeBuffer, GLImageLinuxDMABuffer and
SurfaceFactoryOzone
https://codereview.chromium.org/1072953002/
- Expose file descriptors for gfx::GpuMemoryBuffer::YUV_420 via Map() or GpuMemoryBufferHandle struct
- Add support in GLImageSharedMemory and GLImageMemory through Bind functions
- Look for possible use cases of multiple buffers on Android, Mac, and Win platforms

BUG=439520
TEST=content_unittests  --gtest_filter=GpuMemoryBufferImplTests.*

Review URL: https://codereview.chromium.org/1062423002

Cr-Commit-Position: refs/heads/master@{#324773}

6 files changed, 70 insertions, 2 deletions

diff --git a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_yuv_420_image.txt b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_yuv_420_image.txt
new file mode 100644
index 0000000..5a26516
--- /dev/null
+++ b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_yuv_420_image.txt
@@ -0,0 +1,48 @@
+Name
+
+    CHROMIUM_yuv_420_image
+
+Name Strings
+
+    GL_CHROMIUM_yuv_420_image
+
+Version
+
+    Last Modifed Date: April 10, 2015
+
+Dependencies
+
+    OpenGL ES 2.0 is required.
+
+    GL_CHROMIUM_image is required.
+
+Overview
+
+    This extension provides a new internal image format to use when creating an 
+    image from underlying I420 buffers with YUV components. 
+
+    This extension is useful in conjunction with CreateImageCHROMIUM and
+    CreateGpuMemoryBufferImageCHROMIUM to define the format of GpuMemoryBuffer 
+    backing the image.
+
+New Procedures and Functions
+
+    None.
+
+Errors
+
+    None.
+
+New Tokens
+    
+    Accepted by the <internalformat> parameter of CreateImageCHROMIUM, and 
+    <internalformat> parameter of CreateGpuMemoryBufferImageCHROMIUM:
+        GL_RGB_YUV_420_CHROMIUM 0x78FA
+
+New State
+
+    None.
+
+Revision History
+
+    4/10/2015   Documented the extension
diff --git a/gpu/GLES2/gl2extchromium.h b/gpu/GLES2/gl2extchromium.h
index ec85bf2..415aa63b 100644
--- a/gpu/GLES2/gl2extchromium.h
+++ b/gpu/GLES2/gl2extchromium.h
@@ -136,6 +136,10 @@ typedef void (
 #define GL_SCANOUT_CHROMIUM 0x78F2
 #endif
 
+#ifndef GL_RGB_YUV_420_CHROMIUM
+#define GL_RGB_YUV_420_CHROMIUM 0x78FA
+#endif
+
 #ifdef GL_GLEXT_PROTOTYPES
 GL_APICALL GLuint GL_APIENTRY glCreateGpuMemoryBufferImageCHROMIUM(
     GLsizei width,
diff --git a/gpu/command_buffer/build_gles2_cmd_buffer.py b/gpu/command_buffer/build_gles2_cmd_buffer.py
index 0407033..1bac988 100755
--- a/gpu/command_buffer/build_gles2_cmd_buffer.py
+++ b/gpu/command_buffer/build_gles2_cmd_buffer.py
@@ -1478,6 +1478,7 @@ _NAMED_TYPE_INFO = {
     'type': 'GLenum',
     'valid': [
       'GL_RGB',
+      'GL_RGB_YUV_420_CHROMIUM',
       'GL_RGBA',
     ],
   },
diff --git a/gpu/command_buffer/common/gles2_cmd_utils_implementation_autogen.h b/gpu/command_buffer/common/gles2_cmd_utils_implementation_autogen.h
index 42da99f..c2c6e8d 100644
--- a/gpu/command_buffer/common/gles2_cmd_utils_implementation_autogen.h
+++ b/gpu/command_buffer/common/gles2_cmd_utils_implementation_autogen.h
@@ -329,6 +329,10 @@ static const GLES2Util::EnumToString enum_to_string_table[] = {
      "GL_SYNC_OBJECT_APPLE",
     },
     {
+     0x78FB,
+     "GL_RGBA_YUV_420_CHROMIUM",
+    },
+    {
      0x8DF8,
      "GL_SHADER_BINARY_FORMATS",
     },
@@ -3765,6 +3769,10 @@ static const GLES2Util::EnumToString enum_to_string_table[] = {
      "GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM",
     },
     {
+     0x78FA,
+     "GL_RGB_YUV_420_CHROMIUM",
+    },
+    {
      0x00008000,
      "GL_COVERAGE_BUFFER_BIT_NV",
     },
@@ -4814,7 +4822,9 @@ std::string GLES2Util::GetStringHintTarget(uint32_t value) {
 
 std::string GLES2Util::GetStringImageInternalFormat(uint32_t value) {
   static const EnumToString string_table[] = {
-      {GL_RGB, "GL_RGB"}, {GL_RGBA, "GL_RGBA"},
+      {GL_RGB, "GL_RGB"},
+      {GL_RGB_YUV_420_CHROMIUM, "GL_RGB_YUV_420_CHROMIUM"},
+      {GL_RGBA, "GL_RGBA"},
   };
   return GLES2Util::GetQualifiedEnumString(string_table,
                                            arraysize(string_table), value);
diff --git a/gpu/command_buffer/service/gles2_cmd_validation_implementation_autogen.h b/gpu/command_buffer/service/gles2_cmd_validation_implementation_autogen.h
index 22c5be7..dfa7a59 100644
--- a/gpu/command_buffer/service/gles2_cmd_validation_implementation_autogen.h
+++ b/gpu/command_buffer/service/gles2_cmd_validation_implementation_autogen.h
@@ -276,6 +276,7 @@ static const GLenum valid_hint_target_table[] = {
 
 static const GLenum valid_image_internal_format_table[] = {
     GL_RGB,
+    GL_RGB_YUV_420_CHROMIUM,
     GL_RGBA,
 };
 
diff --git a/gpu/command_buffer/service/image_factory.cc b/gpu/command_buffer/service/image_factory.cc
index 74994ff..ce88f29 100644
--- a/gpu/command_buffer/service/image_factory.cc
+++ b/gpu/command_buffer/service/image_factory.cc
@@ -37,6 +37,8 @@ gfx::GpuMemoryBuffer::Format ImageFactory::ImageFormatToGpuMemoryBufferFormat(
       return gfx::GpuMemoryBuffer::DXT5;
     case GL_ETC1_RGB8_OES:
       return gfx::GpuMemoryBuffer::ETC1;
+    case GL_RGB_YUV_420_CHROMIUM:
+      return gfx::GpuMemoryBuffer::YUV_420;
     default:
       NOTREACHED();
       return gfx::GpuMemoryBuffer::RGBA_8888;
@@ -109,8 +111,10 @@ bool ImageFactory::IsImageSizeValidForGpuMemoryBufferFormat(
     case gfx::GpuMemoryBuffer::RGBA_8888:
     case gfx::GpuMemoryBuffer::BGRA_8888:
     case gfx::GpuMemoryBuffer::RGBX_8888:
-    case gfx::GpuMemoryBuffer::YUV_420:
       return true;
+    case gfx::GpuMemoryBuffer::YUV_420:
+      // U and V planes are subsampled by a factor of 2.
+      return size.width() % 2 == 0 && size.height() % 2 == 0;
   }
 
   NOTREACHED();