Add GL_PROGRAM_COMPLETION_QUERY_CHROMIUM

This makes the query of GL_COMPLETION_STATUS_KHR to programs much
cheaper by minimizing the round-trip to the GPU thread.

Bug: 881152, 957001
Change-Id: Iadfa798af29225e752c710ca5c25f50b3dd3101a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1586630
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#657568}
gfx::Size GLES2DecoderImpl::GetBoundReadFramebufferSize() {
  Framebuffer* framebuffer = GetBoundReadFramebuffer();
  if (framebuffer) {
    return framebuffer->GetFramebufferValidSize();
  } else if (offscreen_target_frame_buffer_.get()) {
    return offscreen_size_;
  } else {
    return surface_->GetSize();
  }
}

gfx::Size GLES2DecoderImpl::GetBoundReadFramebufferSize() {
  Framebuffer* framebuffer = GetBoundReadFramebuffer();
  if (framebuffer) {
    return framebuffer->GetFramebufferValidSize();
  } else if (offscreen_target_frame_buffer_.get()) {
    return offscreen_size_;
  } else {
    return surface_->GetSize();
  }
}
