Some autotests need access to default apps (such as camera).

tools/telemetry/telemetry/core/backends/chrome/cros_browser_backend.py

Index: tools/telemetry/telemetry/core/backends/chrome/cros_browser_backend.py
diff --git a/tools/telemetry/telemetry/core/backends/chrome/cros_browser_backend.py b/tools/telemetry/telemetry/core/backends/chrome/cros_browser_backend.py
index 6cfe0a3ea0808e02452012a669e55c4a0087121f..6c3c6aacc6575b8a0821b9e10d2e29a26433fb5b 100644
--- a/tools/telemetry/telemetry/core/backends/chrome/cros_browser_backend.py
+++ b/tools/telemetry/telemetry/core/backends/chrome/cros_browser_backend.py
@@ -70,9 +70,6 @@ class CrOSBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
             '--enable-smooth-scrolling',
             '--enable-threaded-compositing',
             '--enable-per-tile-painting',
-            # Disables the start page, as well as other external apps that can
-            # steal focus or make measurements inconsistent.
-            '--disable-default-apps',
             # Allow devtools to connect to chrome.
             '--remote-debugging-port=%i' % self._remote_debugging_port,
             # Open a maximized window.
@@ -82,6 +79,11 @@ class CrOSBrowserBackend(chrome_browser_backend.ChromeBrowserBackend):
             # Debug logging.
             '--vmodule=*/chromeos/net/*=2,*/chromeos/login/*=2'])
 
+    # Disables the start page, as well as other external apps that can
+    # steal focus or make measurements inconsistent.
+    if self.browser_options.disable_default_apps:
+      args.append('--disable-default-apps')
+
     # Disable GAIA services unless we're using GAIA login, or if there's an
     # explicit request for it.
     if (self.browser_options.disable_gaia_services and