`buck build chrome` is broken

gistfile1.txt

$ buck build chrome
Watchman not found, please install when using buckd.
See https://github.com/facebook/watchman for details.
(brew install --HEAD watchman on OS X)
[-] PARSING BUILD FILES...FINISHED 1,1s
[+] BUILDING...20,0s
 |=> IDLE
 |=> IDLE
 |=> IDLE
 |=> IDLE
 |=> IDLE
 |=> IDLE
 |=> //gerrit-gwtui:ui_chrome...  19,6s (running gwt-compile[19,6s])
 |=> IDLE
 |=> IDLE
 |=> IDLE
Log:
Exception in thread "DefaultStepRunner-5" java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.io.FileNotFoundException: /home/davido/projects/gerrit/buck-out/gen/gerrit-gwtui/ui_chrome.zip (No such file or directory)
	at com.facebook.buck.util.DefaultFileHashCache.get(DefaultFileHashCache.java:76)
	at com.facebook.buck.rules.RuleKey$Builder.setInputVal(RuleKey.java:290)
	at com.facebook.buck.rules.RuleKey$Builder.setInputs(RuleKey.java:276)
	at com.facebook.buck.rules.AbstractBuildRule.appendToRuleKey(AbstractBuildRule.java:167)
	at com.facebook.buck.rules.AbstractBuildRule.getRuleKeyPair(AbstractBuildRule.java:199)
	at com.facebook.buck.rules.AbstractBuildRule.getRuleKey(AbstractBuildRule.java:180)
	at com.facebook.buck.rules.CachingBuildEngine$1.onSuccess(CachingBuildEngine.java:174)
	at com.facebook.buck.rules.CachingBuildEngine$1.onSuccess(CachingBuildEngine.java:129)
	at com.google.common.util.concurrent.Futures$4.run(Futures.java:1169)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
Caused by: java.util.concurrent.ExecutionException: java.io.FileNotFoundException: /home/davido/projects/gerrit/buck-out/gen/gerrit-gwtui/ui_chrome.zip (No such file or directory)
	at com.google.common.util.concurrent.AbstractFuture$Sync.getValue(AbstractFuture.java:299)
	at com.google.common.util.concurrent.AbstractFuture$Sync.get(AbstractFuture.java:286)
	at com.google.common.util.concurrent.AbstractFuture.get(AbstractFuture.java:116)
	at com.google.common.util.concurrent.Uninterruptibles.getUninterruptibly(Uninterruptibles.java:135)
	at com.google.common.cache.LocalCache$Segment.getAndRecordStats(LocalCache.java:2344)
	at com.google.common.cache.LocalCache$Segment.loadSync(LocalCache.java:2316)
	at com.google.common.cache.LocalCache$Segment.lockedGetOrLoad(LocalCache.java:2278)
	at com.google.common.cache.LocalCache$Segment.get(LocalCache.java:2193)
	at com.google.common.cache.LocalCache.get(LocalCache.java:3932)
	at com.google.common.cache.LocalCache.getOrLoad(LocalCache.java:3936)
	at com.google.common.cache.LocalCache$LocalLoadingCache.get(LocalCache.java:4806)
	at com.facebook.buck.util.DefaultFileHashCache.get(DefaultFileHashCache.java:74)
	... 11 more
Caused by: java.io.FileNotFoundException: /home/davido/projects/gerrit/buck-out/gen/gerrit-gwtui/ui_chrome.zip (No such file or directory)
	at java.io.FileInputStream.open(Native Method)
	at java.io.FileInputStream.<init>(FileInputStream.java:146)
[-] PARSING BUILD FILES...FINISHED 1,1s
[+] BUILDING...23,1s
 |=> IDLE
 |=> IDLE
 |=> IDLE
 |=> IDLE
 |=> //:chrome...  3,0s (checking local cache)
 |=> IDLE
 |=> IDLE
 |=> IDLE
 |=> IDLE
 |=> IDLE