Following 18 tests have started to fail:
telemetry.core.memory_cache_http_server_unittest.MemoryCacheHTTPServerTest.testAbsoluteAndRelativePathsYieldSameURL
telemetry.core.memory_cache_http_server_unittest.MemoryCacheHTTPServerTest.testBasicHostingAndRangeRequests
telemetry.core.platform_unittest.PlatformScreenshotTest.testScreenshotSupported
telemetry.core.tracing_controller_unittest.TracingControllerTest.testBattOrTracing
telemetry.internal.actions.action_runner_unittest.ActionRunnerMeasureMemoryTest.testDeterministicMode
telemetry.internal.actions.action_runner_unittest.ActionRunnerMeasureMemoryTest.testRealisticMode
telemetry.internal.actions.action_runner_unittest.ActionRunnerMeasureMemoryTest.testWithFailedDump
telemetry.internal.actions.action_runner_unittest.ActionRunnerMeasureMemoryTest.testWithoutTracing
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testClickElement
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testEnterText
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testExecuteJavaScript
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testNavigateBack
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testScrollToElement
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testWait
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testWaitForElement
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testWaitForElementWithWrongText
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testWaitForJavaScriptCondition
telemetry.internal.actions.action_runner_unittest.ActionRunnerTest.testWaitForJavaScriptCondition_returnsValue


First failing build:
https://uberchromegw.corp.google.com/i/chromiumos.chromium/builders/amd64-generic-telemetry/builds/12070

Failing stack (all stacks fail in _WaitForBrowserToComeUp):
09:23:12 INFO | [170/1131] telemetry.core.memory_cache_http_server_unittest.MemoryCacheHTTPServerTest.testAbsoluteAndRelativePathsYieldSameURL failed unexpectedly 249.0130s:
09:23:12 INFO |   Failed with BrowserConnectionGoneException while starting the browser backend.
09:23:12 INFO |   Traceback (most recent call last):
09:23:12 INFO |     File "/usr/local/telemetry/src/third_party/catapult/telemetry/telemetry/testing/browser_test_case.py", line 92, in setUpClass
09:23:12 INFO |       current_browser = browser_to_create.Create(options)
09:23:12 INFO |     File "/usr/local/telemetry/src/third_party/catapult/telemetry/telemetry/internal/backends/chrome/cros_browser_finder.py", line 50, in Create
09:23:12 INFO |       self._credentials_path)
09:23:12 INFO |     File "/usr/local/telemetry/src/third_party/catapult/telemetry/telemetry/internal/browser/browser.py", line 59, in __init__
09:23:12 INFO |       self._browser_backend.Start()
09:23:12 INFO |     File "/usr/local/telemetry/src/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
09:23:12 INFO |       return func(*args, **kwargs)
09:23:12 INFO |     File "/usr/local/telemetry/src/third_party/catapult/telemetry/telemetry/internal/backends/chrome/cros_browser_backend.py", line 143, in Start
09:23:12 INFO |       self._WaitForBrowserToComeUp()
09:23:12 INFO |     File "/usr/local/telemetry/src/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py", line 52, in traced_function
09:23:12 INFO |       return func(*args, **kwargs)
09:23:12 INFO |     File "/usr/local/telemetry/src/third_party/catapult/telemetry/telemetry/internal/backends/chrome/chrome_browser_backend.py", line 164, in _WaitForBrowserToComeUp
09:23:12 INFO |       raise exceptions.BrowserConnectionGoneException(self.browser, e)
09:23:12 INFO |   BrowserConnectionGoneException: Timed out while waiting 240s for HasBrowserFinishedLaunching.