Enable no-implicit-coercion for all files

R=mathias@chromium.org,jacktfranklin@chromium.org

Fixed: 1082789
Change-Id: I2cf3c221e748654c296f35c3f149b1f76684f4a3
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2612903
Reviewed-by: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Commit-Queue: Tim van der Lippe <tvanderlippe@chromium.org>
diff --git a/scripts/watch_build.js b/scripts/watch_build.js
index 798f174..3bc2bed 100644
--- a/scripts/watch_build.js
+++ b/scripts/watch_build.js
@@ -34,7 +34,7 @@
 
   // If the exitCode is null, autoninja is still running so stop it
   // and try to restart it again.
-  const ninjaProcessExists = !!(autoninja && autoninja.pid);
+  const ninjaProcessExists = Boolean(autoninja && autoninja.pid);
   if (ninjaProcessExists) {
     const isRunning = ninjaProcessExists && autoninja.exitCode === null;
     if (isRunning) {