Auto merge of #12507 - larsbergstrom:remove_clipboard, r=metajack

Remove clipboard crate to due disallowed usage of GPL code

<!-- Please describe your changes on the following line: -->
Fixes #7578, removing usage of rust-clipboard, which contains a disallowed dependency on GPL code.

r? @metajack

---
<!-- 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).

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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because it's a dependency removal

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components/constellation/constellation.rs

@@ -13,7 +13,6 @@ use backtrace::Backtrace;
 use canvas::canvas_paint_thread::CanvasPaintThread;
 use canvas::webgl_paint_thread::WebGLPaintThread;
 use canvas_traits::CanvasMsg;
-use clipboard::ClipboardContext;
 use compositing::SendableFrameTree;
 use compositing::compositor_thread::CompositorProxy;
 use compositing::compositor_thread::Msg as ToCompositorMsg;
@@ -172,9 +171,6 @@ pub struct Constellation<Message, LTF, STF> {
 
     window_size: WindowSizeData,
 
-    /// Means of accessing the clipboard
-    clipboard_ctx: Option<ClipboardContext>,
-
     /// Bits of state used to interact with the webdriver implementation
     webdriver: WebDriverData,
 
@@ -476,11 +472,6 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
                         ScaleFactor::new(opts::get().device_pixels_per_px.unwrap_or(1.0)),
                 },
                 phantom: PhantomData,
-                clipboard_ctx: if state.supports_clipboard {
-                    ClipboardContext::new().ok()
-                } else {
-                    None
-                },
                 webdriver: WebDriverData::new(),
                 scheduler_chan: TimerScheduler::start(),
                 child_processes: Vec::new(),
@@ -851,26 +842,11 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
                 }
             }
             FromScriptMsg::GetClipboardContents(sender) => {
-                let result = match self.clipboard_ctx {
-                    Some(ref ctx) => match ctx.get_contents() {
-                        Ok(result) => result,
-                        Err(e) => {
-                            warn!("Error getting clipboard contents ({}), defaulting to empty string", e);
-                            "".to_owned()
-                        },
-                    },
-                    None => "".to_owned()
-                };
-                if let Err(e) = sender.send(result) {
+                if let Err(e) = sender.send("".to_owned()) {
                     warn!("Failed to send clipboard ({})", e);
                 }
             }
-            FromScriptMsg::SetClipboardContents(s) => {
-                if let Some(ref mut ctx) = self.clipboard_ctx {
-                    if let Err(e) = ctx.set_contents(s) {
-                        warn!("Error setting clipboard contents ({})", e);
-                    }
-                }
+            FromScriptMsg::SetClipboardContents(_) => {
             }
             FromScriptMsg::SetVisible(pipeline_id, visible) => {
                 debug!("constellation got set visible messsage");