The test debugger-eval-on-call-frame-inside-iframe.js (both the normal test and virtual/mojo-loading) has recently been flakily failing on all platforms. In the past, it has only been failing on Windows. The failure looks like this:

@@ -18,12 +18,13 @@
 setTimeout (async)
 scheduleTestFunction @ VM:3
 (anonymous) @ VM:1
+error: Attempt to select missing item
 
 === Evaluating on top frame ===
-dir() = undefined
-dirxml() = "overridden dirxml() in top frame"
-table = 
-clear = "local in top frame"
+dir() = "overridden dir() in iframe"
+dirxml() = undefined
+table = "local in iframe"
+clear = 
 x: = VM:1 Uncaught SyntaxError: Unexpected end of input
     at Object.pauseInsideIframe (<anonymous>:6:5)
     at testFunction (debugger-eval-on-cal…inside-iframe.js:35)


The first instance is from rev 519189, so it would be one of the devtools changes not long before it.

Suspect candidates: https://crrev.com/5eae5f19 https://crrev.com/820c5f13 https://crrev.com/1cd17e61
Git log: https://chromium.googlesource.com/chromium/src/+log/81c9f48e22bda64beed7bda744edd81fd107400e
Flakiness dashboard: https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&showAllRuns=true&tests=http%2Ftests%2Fdevtools%2Fsources%2Fdebugger-pause%2Fdebugger-eval-on-call-frame-inside-iframe.js
Sample failed run: https://storage.googleapis.com/chromium-layout-test-archives/Linux_Tests/65132/layout-test-results/results.html