Allow creating GLImage-backed textures with glTexStorage2D.

gpu/command_buffer/service/texture_manager.h

Index: gpu/command_buffer/service/texture_manager.h
diff --git a/gpu/command_buffer/service/texture_manager.h b/gpu/command_buffer/service/texture_manager.h
index 77b7e7fef5c9dcedcbbbec17deaff73376f212e5..45187e69b8b8cee1a1ccbb8e4d050478fc568f45 100644
--- a/gpu/command_buffer/service/texture_manager.h
+++ b/gpu/command_buffer/service/texture_manager.h
@@ -165,6 +165,8 @@ class GPU_EXPORT Texture final : public TextureBase {
     return usage_;
   }
 
+  GLint buffer_usage() const { return buffer_usage_; }
+
   GLenum compare_func() const {
     return sampler_state_.compare_func;
   }
@@ -612,6 +614,7 @@ class GPU_EXPORT Texture final : public TextureBase {
   GLenum swizzle_g_;
   GLenum swizzle_b_;
   GLenum swizzle_a_;
+  GLint buffer_usage_ = GL_NONE;
 
   // The maximum level that has been set.
   GLint max_level_set_;