gpu: support R16 GPUMemoryBuffer

ui/gl/gl_image_memory.cc

Index: ui/gl/gl_image_memory.cc
diff --git a/ui/gl/gl_image_memory.cc b/ui/gl/gl_image_memory.cc
index 20e694ff2fc322d622370749b3d97c5345492f67..170e3c6949939b0f1aacd1e5f27e39fa0332cc55 100644
--- a/ui/gl/gl_image_memory.cc
+++ b/ui/gl/gl_image_memory.cc
@@ -45,6 +45,7 @@ bool ValidFormat(gfx::BufferFormat format) {
     case gfx::BufferFormat::DXT5:
     case gfx::BufferFormat::ETC1:
     case gfx::BufferFormat::R_8:
+    case gfx::BufferFormat::R_16:
     case gfx::BufferFormat::RG_88:
     case gfx::BufferFormat::BGR_565:
     case gfx::BufferFormat::RGBA_4444:
@@ -73,6 +74,7 @@ bool IsCompressedFormat(gfx::BufferFormat format) {
     case gfx::BufferFormat::ETC1:
       return true;
     case gfx::BufferFormat::R_8:
+    case gfx::BufferFormat::R_16:
     case gfx::BufferFormat::RG_88:
     case gfx::BufferFormat::BGR_565:
     case gfx::BufferFormat::RGBA_4444:
@@ -107,6 +109,8 @@ GLenum TextureFormat(gfx::BufferFormat format) {
       return GL_ETC1_RGB8_OES;
     case gfx::BufferFormat::R_8:
       return GL_RED;
+    case gfx::BufferFormat::R_16:
+      return GL_R16_EXT;
     case gfx::BufferFormat::RG_88:
       return GL_RG;
     case gfx::BufferFormat::RGBA_4444:
@@ -142,6 +146,7 @@ GLenum DataFormat(gfx::BufferFormat format) {
     case gfx::BufferFormat::BGRA_8888:
     case gfx::BufferFormat::RGBA_F16:
     case gfx::BufferFormat::R_8:
+    case gfx::BufferFormat::R_16:
     case gfx::BufferFormat::RG_88:
     case gfx::BufferFormat::ATC:
     case gfx::BufferFormat::ATCIA:
@@ -173,6 +178,8 @@ GLenum DataType(gfx::BufferFormat format) {
     case gfx::BufferFormat::R_8:
     case gfx::BufferFormat::RG_88:
       return GL_UNSIGNED_BYTE;
+    case gfx::BufferFormat::R_16:
+      return GL_UNSIGNED_SHORT;
     case gfx::BufferFormat::RGBA_F16:
       return GL_HALF_FLOAT_OES;
     case gfx::BufferFormat::ATC:
@@ -194,6 +201,7 @@ GLenum DataType(gfx::BufferFormat format) {
 GLint DataRowLength(size_t stride, gfx::BufferFormat format) {
   switch (format) {
     case gfx::BufferFormat::RG_88:
+    case gfx::BufferFormat::R_16:
     case gfx::BufferFormat::BGR_565:
     case gfx::BufferFormat::RGBA_4444:
       return base::checked_cast<GLint>(stride) / 2;
@@ -319,6 +327,7 @@ std::unique_ptr<uint8_t[]> GLES2Data(const gfx::Size& size,
     case gfx::BufferFormat::BGRA_8888:
     case gfx::BufferFormat::RGBA_F16:
     case gfx::BufferFormat::R_8:
+    case gfx::BufferFormat::R_16:
     case gfx::BufferFormat::RG_88: {
       size_t gles2_data_stride =
           RowSizeForBufferFormat(size.width(), format, 0);