Auto merge of #10448 - matthiaskrgr:travis, r=aneeshusa

travis: add and run script which checks if listed files contain "unwrap". Should fix #10446.

Unfortunately there is a lot of python code in tidy.py that I don't understand yet, so I simply wrote a bash script to do the job and hooked it up in travis.yml.

Tests are expected to fail:

````
components/compositing/compositor.rs:758:        self.pipeline_details.get_mut(&pipeline_id).unwrap()
components/compositing/compositor.rs:2194:        RgbImage::from_raw(width as u32, height as u32, pixels).unwrap()
components/compositing/pipeline.rs:130:        let (paint_shutdown_chan, paint_shutdown_port) = ipc::channel().unwrap();
components/compositing/pipeline.rs:131:        let (layout_shutdown_chan, layout_shutdown_port) = ipc::channel().unwrap();
components/compositing/pipeline.rs:132:        let (pipeline_chan, pipeline_port) = ipc::channel().unwrap();
components/compositing/pipeline.rs:133:        let (script_to_compositor_chan, script_to_compositor_port) = ipc::channel().unwrap();
components/compositing/pipeline.rs:151:            let (script_to_devtools_chan, script_to_devtools_port) = ipc::channel().unwrap();
components/compositing/pipeline.rs:154:                let message: ScriptToDevtoolsControlMsg = message.to().unwrap();
components/compositing/pipeline.rs:155:                devtools_chan.send(DevtoolsControlMsg::FromScript(message)).unwrap()
components/compositing/pipeline.rs:161:            ipc::channel().unwrap();
components/compositing/pipeline.rs:174:                    pipeline_port: mem::replace(&mut pipeline_port, None).unwrap(),
components/compositing/pipeline.rs:180:                           .unwrap();
components/compositing/pipeline.rs:184:                let (script_chan, script_port) = ipc::channel().unwrap();
components/compositing/pipeline.rs:190:            ipc::channel().unwrap();
components/compositing/pipeline.rs:298:        let (sender, receiver) = ipc::channel().unwrap();
components/compositing/pipeline.rs:300:        receiver.recv().unwrap();
components/compositing/pipeline.rs:315:        let _ = self.script_chan.send(ConstellationControlMsg::Freeze(self.id)).unwrap();
components/compositing/pipeline.rs:319:        let _ = self.script_chan.send(ConstellationControlMsg::Thaw(self.id)).unwrap();
components/compositing/pipeline.rs:323:        let _ = self.script_chan.send(ConstellationControlMsg::ExitPipeline(self.id)).unwrap();
components/compositing/pipeline.rs:326:        let _ = layout_channel.send(LayoutControlMsg::ExitNow).unwrap();
components/compositing/pipeline.rs:343:        let index = self.children.iter().position(|id| *id == frame_id).unwrap();
components/compositing/pipeline.rs:355:        self.script_chan.send(event).unwrap();
components/compositing/pipeline.rs:402:            control_port: mem::replace(&mut self.script_port, None).unwrap(),
components/compositing/pipeline.rs:423:                                  self.pipeline_port.unwrap(),
components/compositing/pipeline.rs:437:            self.script_content_process_shutdown_port.recv().unwrap();
components/compositing/pipeline.rs:438:            self.layout_content_process_shutdown_port.recv().unwrap();
components/compositing/constellation.rs:464:            IpcOneShotServer::<IpcSender<UnprivilegedPipelineContent>>::new().unwrap();
components/compositing/constellation.rs:468:            let mut command = sandbox::Command::me().unwrap();
components/compositing/constellation.rs:474:            let path_to_self = env::current_exe().unwrap();
components/compositing/constellation.rs:478:            ChildProcess::Unsandboxed(child_process.spawn().unwrap())
components/compositing/constellation.rs:482:        let (_receiver, sender) = server.accept().unwrap();
components/compositing/constellation.rs:835:            stderr.write_all("Pipeline failed in hard-fail mode.  Crashing!\n".as_bytes()).unwrap();
components/compositing/constellation.rs:1621:            let (sender, receiver) = ipc::channel().unwrap();
components/compositing/constellation.rs:1657:                        let (sender, receiver) = ipc::channel().unwrap();
components/compositing/constellation.rs:1659:                        layout_chan.send(LayoutControlMsg::GetCurrentEpoch(sender)).unwrap();
components/compositing/constellation.rs:1660:                        let layout_thread_epoch = receiver.recv().unwrap();
components/compositing/constellation.rs:1838:                let (chan, port) = ipc::channel().unwrap();
````

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.travis.yml

@@ -16,6 +16,7 @@ matrix:
          - ./mach test-compiletest
          - bash etc/ci/lockfile_changed.sh
          - bash etc/ci/manifest_changed.sh
+         - bash etc/ci/check_no_unwrap.sh
       cache:
         directories:
           - .cargo

etc/ci/check_no_unwrap.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+#
+# Make sure listed files do not contain "unwrap"
+set -o errexit
+set -o nounset
+set -o pipefail
+
+cd $(git rev-parse --show-toplevel) # cd into repo root so make sure paths works in any case
+
+# files that should not contain "unwrap"
+FILES=("components/compositing/compositor.rs"
+       "components/compositing/pipeline.rs"
+       "components/compositing/constellation.rs")
+
+! grep -n "unwrap(" "${FILES[@]}"