Save / restore state when updating opaque framebuffer bindings

[asajeffrey]

This saves and restores the WebGL bindings for texture and framebuffer when beginning a webxr frame.

---

• ./mach build -d does not report any errors
• ./mach test-tidy does not report any errors
• These changes fix #27286
• These changes do not require tests because we don't reftest hololens (it would be nice if we did!)

[highfive]

Heads up! This PR modifies the following files:

• @KiChjang: components/script/dom/xrwebgllayer.rs

[highfive]

Warning

• These commits modify script code, but no tests are modified. Please consider adding a test!

[asajeffrey]

Also updates webxr to pull in servo/webxr#185

[Manishearth]

@bors r+

nice catch!

[jdm]

@bors-servo r=Manishearth

[bors-servo]

📌 Commit f2d7331 has been approved by Manishearth

[bors-servo]

⌛ Testing commit f2d7331 with merge 91d3c0b...

[bors-servo]

💔 Test failed - status-taskcluster

[jdm]

  ▶ CRASH [expected OK] /_mozilla/webxr/layers.html
  │ 
  │ _RegisterApplication(), FAILED TO establish the default connection to the WindowServer, _CGSDefaultConnection() is NULL.
  │ called `Result::unwrap()` on an `Err` value: InvalidEnum (thread ScriptThread PipelineId { namespace_id: PipelineNamespaceId(1), index: PipelineIndex(1) }, at components/script/dom/xrwebgllayer.rs:239)
  │    0: <servo::backtrace::Print as core::fmt::Debug>::fmt
  │    1: core::fmt::write
  │    2: std::io::Write::write_fmt
  │    3: servo::backtrace::print
  │    4: servo::main::{{closure}}
  │    5: std::panicking::rust_panic_with_hook
  │    6: _rust_begin_unwind
  │    7: core::panicking::panic_fmt
  │    8: core::option::expect_none_failed
  │    9: script::dom::xrwebgllayer::XRWebGLLayer::begin_frame
  │   10: script::dom::xrrenderstate::XRRenderState::with_layers
  │   11: <script::dom::xrsession::XRSession::setup_raf_loop::{{closure}}::xr_raf_callback<F> as script::task::TaskOnce>::run_once
  │   12: <T as script::task::TaskBox>::run_box
  │   13: script::script_thread::ScriptThread::handle_msgs
  │   14: profile_traits::mem::ProfilerChan::run_with_memory_reporting
  │   15: std::sys_common::backtrace::__rust_begin_short_backtrace
  │   16: core::ops::function::FnOnce::call_once{{vtable.shim}}
  │   17: std::sys::unix::thread::Thread::new::thread_start
  │   18: __pthread_body
  │   19: __pthread_start
  │ [2020-07-18T03:03:35Z ERROR servo] called `Result::unwrap()` on an `Err` value: InvalidEnum
  └ Pipeline failed in hard-fail mode.  Crashing!

  ▶ CRASH [expected OK] /_mozilla/webxr/obtain_frame.html
  │ 
  │ _RegisterApplication(), FAILED TO establish the default connection to the WindowServer, _CGSDefaultConnection() is NULL.
  │ called `Result::unwrap()` on an `Err` value: InvalidEnum (thread ScriptThread PipelineId { namespace_id: PipelineNamespaceId(1), index: PipelineIndex(1) }, at components/script/dom/xrwebgllayer.rs:239)
  │    0: <servo::backtrace::Print as core::fmt::Debug>::fmt
  │    1: core::fmt::write
  │    2: std::io::Write::write_fmt
  │    3: servo::backtrace::print
  │    4: servo::main::{{closure}}
  │    5: std::panicking::rust_panic_with_hook
  │    6: _rust_begin_unwind
  │    7: core::panicking::panic_fmt
  │    8: core::option::expect_none_failed
  │    9: script::dom::xrwebgllayer::XRWebGLLayer::begin_frame
  │   10: <script::dom::xrsession::XRSession::setup_raf_loop::{{closure}}::xr_raf_callback<F> as script::task::TaskOnce>::run_once
  │   11: <T as script::task::TaskBox>::run_box
  │   12: script::script_thread::ScriptThread::handle_msgs
  │   13: profile_traits::mem::ProfilerChan::run_with_memory_reporting
  │   14: std::sys_common::backtrace::__rust_begin_short_backtrace
  │   15: core::ops::function::FnOnce::call_once{{vtable.shim}}
  │   16: std::sys::unix::thread::Thread::new::thread_start
  │   17: __pthread_body
  │   18: __pthread_start
  │ [2020-07-18T03:04:09Z ERROR servo] called `Result::unwrap()` on an `Err` value: InvalidEnum
  └ Pipeline failed in hard-fail mode.  Crashing!

[asajeffrey]

Sigh, crashes on macos due to surface textures there being GL_RECTANGLE not GL_TEXTURE2D. @bors-servo r=Manishearth

[bors-servo]

📌 Commit f015275 has been approved by Manishearth

[bors-servo]

⌛ Testing commit f015275 with merge 735427c...

[bors-servo]

💔 Test failed - status-taskcluster

[jdm]

@bors-servo retry

• #27315

[bors-servo]

⌛ Testing commit f015275 with merge 48bf169...

[bors-servo]

☀️ Test successful - status-taskcluster
Approved by: Manishearth
Pushing 48bf169 to master...