Implement WEBGL_compressed_texture_s3tc_srgb

gpu/command_buffer/service/texture_manager.cc

Index: gpu/command_buffer/service/texture_manager.cc
diff --git a/gpu/command_buffer/service/texture_manager.cc b/gpu/command_buffer/service/texture_manager.cc
index 67615bf25d6a3a39a8ca9772d174c0e343a8954c..f45852e78a5aefc96fb15115e78c4ace879ba1dc 100644
--- a/gpu/command_buffer/service/texture_manager.cc
+++ b/gpu/command_buffer/service/texture_manager.cc
@@ -3162,6 +3162,7 @@ GLenum TextureManager::ExtractFormatFromStorageFormat(GLenum internalformat) {
     case GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG:
     case GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG:
     case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+    case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
     case GL_ETC1_RGB8_OES:
     case GL_RGB:
     case GL_RGB8:
@@ -3189,6 +3190,9 @@ GLenum TextureManager::ExtractFormatFromStorageFormat(GLenum internalformat) {
     case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
     case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
+    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
+    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
     case GL_RGBA:
     case GL_RGBA8:
     case GL_SRGB8_ALPHA8: