Pass initial size and GPU preference via context attributes

gpu/command_buffer/common/gles2_cmd_utils.h

Index: gpu/command_buffer/common/gles2_cmd_utils.h
diff --git a/gpu/command_buffer/common/gles2_cmd_utils.h b/gpu/command_buffer/common/gles2_cmd_utils.h
index 6f7313006934f9fa689432b1125db66d57e4aa5a..1ec812a8bfd2f565df860ca939948e0614b40fbd 100644
--- a/gpu/command_buffer/common/gles2_cmd_utils.h
+++ b/gpu/command_buffer/common/gles2_cmd_utils.h
@@ -18,6 +18,8 @@
 #include "base/macros.h"
 #include "base/numerics/safe_math.h"
 #include "gpu/command_buffer/common/gles2_utils_export.h"
+#include "ui/gfx/geometry/size.h"
+#include "ui/gl/gpu_preference.h"
 
 namespace gpu {
 namespace gles2 {
@@ -307,6 +309,8 @@ struct GLES2_UTILS_EXPORT ContextCreationAttribHelper {
 
   bool Parse(const std::vector<int32_t>& attribs);
 
+  gfx::Size offscreen_framebuffer_size;
+  gl::GpuPreference gpu_preference;
   // -1 if invalid or unspecified.
   int32_t alpha_size;
   int32_t blue_size;