Auto merge of #21688 - paulrouget:rm-clipboard, r=jdm

Let the clipboard crate handle the lack of clipboard support

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/21688)
<!-- Reviewable:end -->

components/compositing/windowing.rs

@@ -136,8 +136,6 @@ pub trait WindowMethods {
     fn create_event_loop_waker(&self) -> Box<EventLoopWaker>;
     /// Get the coordinates of the native window, the screen and the framebuffer.
     fn get_coordinates(&self) -> EmbedderCoordinates;
-    /// Does this window support a clipboard
-    fn supports_clipboard(&self) -> bool;
     /// Set whether the application is currently animating.
     /// Typically, when animations are active, the window
     /// will want to avoid blocking on UI events, and just

components/constellation/constellation.rs

@@ -374,10 +374,6 @@ pub struct InitialConstellationState {
 
     /// A channel to the webgl thread.
     pub webvr_chan: Option<IpcSender<WebVRMsg>>,
-
-    /// Whether the constellation supports the clipboard.
-    /// TODO: this field is not used, remove it?
-    pub supports_clipboard: bool,
 }
 
 /// Data needed for webdriver
@@ -621,16 +617,12 @@ where
                         ),
                     },
                     phantom: PhantomData,
-                    clipboard_ctx: if state.supports_clipboard {
-                        match ClipboardContext::new() {
-                            Ok(c) => Some(c),
-                            Err(e) => {
-                                warn!("Error creating clipboard context ({})", e);
-                                None
-                            },
-                        }
-                    } else {
-                        None
+                    clipboard_ctx: match ClipboardContext::new() {
+                        Ok(c) => Some(c),
+                        Err(e) => {
+                            warn!("Error creating clipboard context ({})", e);
+                            None
+                        },
                     },
                     webdriver: WebDriverData::new(),
                     scheduler_chan: TimerScheduler::start(),

components/servo/lib.rs

@@ -151,7 +151,6 @@ where
             create_compositor_channel(window.create_event_loop_waker());
         let (embedder_proxy, embedder_receiver) =
             create_embedder_channel(window.create_event_loop_waker());
-        let supports_clipboard = window.supports_clipboard();
         let time_profiler_chan = profile_time::Profiler::create(
             &opts.time_profiling,
             opts.time_profiler_trace_path.clone(),
@@ -221,7 +220,6 @@ where
             mem_profiler_chan.clone(),
             debugger_chan,
             devtools_chan,
-            supports_clipboard,
             &mut webrender,
             webrender_document,
             webrender_api_sender,
@@ -493,7 +491,6 @@ fn create_constellation(
     mem_profiler_chan: mem::ProfilerChan,
     debugger_chan: Option<debugger::Sender>,
     devtools_chan: Option<Sender<devtools_traits::DevtoolsControlMsg>>,
-    supports_clipboard: bool,
     webrender: &mut webrender::Renderer,
     webrender_document: webrender_api::DocumentId,
     webrender_api_sender: webrender_api::RenderApiSender,
@@ -569,7 +566,6 @@ fn create_constellation(
         private_resource_threads,
         time_profiler_chan,
         mem_profiler_chan,
-        supports_clipboard,
         webrender_document,
         webrender_api_sender,
         webgl_threads,

ports/libsimpleservo/src/api.rs

@@ -437,11 +437,6 @@ impl WindowMethods for ServoCallbacks {
         self.host_callbacks.flush();
     }
 
-    fn supports_clipboard(&self) -> bool {
-        debug!("WindowMethods::supports_clipboard");
-        false
-    }
-
     fn create_event_loop_waker(&self) -> Box<EventLoopWaker> {
         debug!("WindowMethods::create_event_loop_waker");
         self.waker.clone()

ports/servo/glutin_app/window.rs

@@ -813,10 +813,6 @@ impl WindowMethods for Window {
     ) -> bool {
         true
     }
-
-    fn supports_clipboard(&self) -> bool {
-        true
-    }
 }
 
 fn winit_phase_to_touch_event_type(phase: TouchPhase) -> TouchEventType {