Tab Search: increase benchmark trace buffer size

On windows 10 perf bots, it takes significant longer time to run the
tab_search:top100:2020 story, which ofter leads to buffer overrun
failure. This CL increases the buffer size to reduce the chance of the
failure.

Bug: 1152598
Change-Id: I4a15c0e6164661ea344df2461d79ece11e9e6eac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2596827
Commit-Queue: Yuheng Huang <yuhengh@chromium.org>
Reviewed-by: John Chen <johnchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#838150}

tools/perf/benchmarks/tab_search.py

@@ -55,7 +55,7 @@ class TabSearch(perf_benchmark.PerfBenchmark):
     options.config.chrome_trace_config.EnableUMAHistograms(
         *TAB_SEARCH_BENCHMARK_UMA)
     # Add more buffer since we are opening a lot of tabs.
-    options.config.chrome_trace_config.SetTraceBufferSizeInKb(300 * 1024)
+    options.config.chrome_trace_config.SetTraceBufferSizeInKb(600 * 1024)
     options.SetTimelineBasedMetrics(['webuiMetric', 'umaMetric'])
     return options