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, 5 insertions, 8 deletions

diff --git a/devices/src/virtio/rng.rs b/devices/src/virtio/rng.rs
index 19f83bc..21d5c28 100644
--- a/devices/src/virtio/rng.rs
+++ b/devices/src/virtio/rng.rs
@@ -85,14 +85,11 @@ impl Worker {
             Kill,
         }
 
-        let poll_ctx: PollContext<Token> = match PollContext::new()
-            .and_then(|pc| pc.add(&queue_evt, Token::QueueAvailable).and(Ok(pc)))
-            .and_then(|pc| {
-                pc.add(&self.interrupt_resample_evt, Token::InterruptResample)
-                    .and(Ok(pc))
-            })
-            .and_then(|pc| pc.add(&kill_evt, Token::Kill).and(Ok(pc)))
-        {
+        let poll_ctx: PollContext<Token> = match PollContext::build_with(&[
+            (&queue_evt, Token::QueueAvailable),
+            (&self.interrupt_resample_evt, Token::InterruptResample),
+            (&kill_evt, Token::Kill),
+        ]) {
             Ok(pc) => pc,
             Err(e) => {
                 error!("failed creating PollContext: {}", e);