Disable Harmony UI dialog for telemetry tests.

All tests complains about no MR dialog because Harmony UI kicks in.

Change-Id: Ibcef272966f802a8fa52b8ade0f2a8247c25ca78
Reviewed-on: https://chromium-review.googlesource.com/c/1281181Reviewed-by: Takumi Fujimoto <takumif@chromium.org>
Commit-Queue: Clifford Cheng <cliffordcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599750}

chrome/test/media_router/telemetry/benchmarks/media_router_benchmark.py

@@ -32,6 +32,7 @@ class _BaseCastBenchmark(perf_benchmark.PerfBenchmark):
             'Release', 'mr_extension', 'release'),
              os.path.join(path_util.GetChromiumSrcDir(), 'out',
              'Release', 'media_router', 'telemetry_extension')]),
+        '--disable-features=ViewsCastDialog',
         '--whitelisted-extension-id=enhhojjnijigcajfphajepfemndkmdlo',
         '--media-router=1',
         '--enable-stats-collection-bindings'
@@ -108,6 +109,7 @@ class CPUMemoryBenckmark(perf_benchmark.PerfBenchmark):
         '--load-extension=' +
              os.path.join(path_util.GetChromiumSrcDir(), 'out',
              'Release', 'media_router', 'telemetry_extension'),
+        '--disable-features=ViewsCastDialog',
         '--media-router=0',
         '--enable-stats-collection-bindings'
     ])