edition: Use dyn syntax for trait objects

Found by running: `cargo rustc -- -D bare_trait_objects`

Bare trait objects like `&Trait` and `Box<Trait>` are soft-deprecated in
2018 edition and will start warning at some point.

As part of this, I replaced `Box<Trait + 'static>` with `Box<dyn Trait>`
because the 'static bound is implied for boxed trait objects.

TEST=cargo check --all-features
TEST=cargo check --target aarch64-unknown-linux-gnu
TEST=local kokoro

Change-Id: I41c4f13530bece8a34a8ed1c1afd7035b8f86f19
Reviewed-on: https://chromium-review.googlesource.com/1513059
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: David Tolnay <dtolnay@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: David Tolnay <dtolnay@chromium.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/devices/src/pci/ac97_bus_master.rs b/devices/src/pci/ac97_bus_master.rs
index 7d169a3..5f7f444 100644
--- a/devices/src/pci/ac97_bus_master.rs
+++ b/devices/src/pci/ac97_bus_master.rs
@@ -74,7 +74,7 @@ enum PlaybackError {
     // Failure reading samples from guest memory.
     ReadingGuestSamples(data_model::VolatileMemoryError),
     // Failure to get an buffer from the stream.
-    StreamError(Box<Error>),
+    StreamError(Box<dyn Error>),
     // Failure writing to the audio output.
     WritingOutput(std::io::Error),
 }
@@ -406,7 +406,7 @@ impl Ac97BusMaster {
         self.regs.lock().glob_cnt = new_glob_cnt;
     }
 
-    fn start_audio(&mut self, func: Ac97Function, mixer: &Ac97Mixer) -> Result<(), Box<Error>> {
+    fn start_audio(&mut self, func: Ac97Function, mixer: &Ac97Mixer) -> Result<(), Box<dyn Error>> {
         const AUDIO_THREAD_RTPRIO: u16 = 12; // Matches other cros audio clients.
 
         match func {