tree-wide: use PollContext::build_with where possible

The old method of creating a PollContext and calling `add` inside of
`and_then` chains was an ugly way handle the Results that can crop up
after each call. The `build_with` function is equivalent but operates on
a slice which has way less boilerplate.

TEST=./build_test
BUG=None

Change-Id: I8b0d6532680e04c501187397bd211014a2363c25
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1715581
Tested-by: Zach Reizner <zachr@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Auto-Submit: Zach Reizner <zachr@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Commit-Queue: Zach Reizner <zachr@chromium.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/devices/src/pit.rs b/devices/src/pit.rs
index 63f31f5..86ad4c5 100644
--- a/devices/src/pit.rs
+++ b/devices/src/pit.rs
@@ -745,10 +745,9 @@ impl Worker {
             Kill,
         }
 
-        let poll_ctx: PollContext<Token> = PollContext::new()
-            .and_then(|pc| pc.add(&self.fd, Token::TimerExpire).and(Ok(pc)))
-            .and_then(|pc| pc.add(&kill_evt, Token::Kill).and(Ok(pc)))
-            .map_err(PitError::CreatePollContext)?;
+        let poll_ctx: PollContext<Token> =
+            PollContext::build_with(&[(&self.fd, Token::TimerExpire), (&kill_evt, Token::Kill)])
+                .map_err(PitError::CreatePollContext)?;
 
         loop {
             let events = poll_ctx.wait().map_err(PitError::PollError)?;