Reduce thread count in offlineaudiocontext-thread-smoke-test.html

Some try bots have been timed out on this test. Reduced the thread
count to avoid such failure. (2500 -> 1000)

Bug: 741699
Change-Id: Iec63bd67c991d43932803b734826d6d385e5cc03
Reviewed-on: https://chromium-review.googlesource.com/568586Reviewed-by: Raymond Toy <rtoy@chromium.org>
Commit-Queue: Hongchan Choi <hongchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486112}

third_party/WebKit/LayoutTests/FlagExpectations/enable-features=NetworkService

@@ -3354,7 +3354,6 @@ Bug(none) webaudio/IIRFilter/iirfilter.html [ Timeout ]
 Bug(none) webaudio/MediaElementAudioSource/mediaelementaudiosourcenode.html [ Timeout ]
 Bug(none) webaudio/MediaStreamAudioDestination/mediastreamaudiodestinationnode.html [ Timeout ]
 Bug(none) webaudio/MediaStreamAudioSource/mediastreamaudiosourcenode.html [ Timeout ]
-Bug(none) webaudio/OfflineAudioContext/offlineaudiocontext-thread-smoke-test.html [ Timeout ]
 Bug(none) webaudio/Panner/pannernode-basic.html [ Timeout ]
 Bug(none) webaudio/PeriodicWave/periodicwave-lengths.html [ Timeout ]
 Bug(none) webaudio/StereoPanner/stereopannernode-basic.html [ Timeout ]

third_party/WebKit/LayoutTests/webaudio/OfflineAudioContext/offlineaudiocontext-thread-smoke-test.html

@@ -19,8 +19,10 @@
       const numberOfChannels = 1;
       const renderLength = 1;
 
-      // Create 2500 contexts in total. 58.0.3029 on OSX crashes around 2030.
-      const maxNumberOfContexts = 2500;
+      // Create 1000 contexts in total. 58.0.3029 on OSX crashes around 2030,
+      // but creating ~2000 threads makes some try bots time-out.
+      // (crbug.com/741699)
+      const maxNumberOfContexts = 1000;
 
       let contexts = [];
 
@@ -40,7 +42,7 @@
       audit.define(
           {
             label: 'context-creation-smoketest',
-            description: 
+            description:
                 'Creating ' + maxNumberOfContexts + ' contexts up front.'
           },
           (task, should) => {