Devserver: Add perf_data dep to telemetry source list.

Splitting telemetry and perf data into separate deps, both need to
be installed for telemetry to run.

BUG=chromium:223237
TEST=Local devserver

Change-Id: I8f6f7531526cb345fd42a31e1172467360dc07c7
Reviewed-on: https://gerrit.chromium.org/gerrit/46328
Commit-Queue: Simran Basi <sbasi@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Tested-by: Simran Basi <sbasi@chromium.org>
diff --git a/devserver.py b/devserver.py
index 8378b76..d3ad97c 100755
--- a/devserver.py
+++ b/devserver.py
@@ -34,7 +34,8 @@
 TELEMETRY_FOLDER = 'telemetry_src'
 TELEMETRY_DEPS = ['dep-telemetry_dep.tar.bz2',
                   'dep-page_cycler_dep.tar.bz2',
-                  'dep-chrome_test.tar.bz2']
+                  'dep-chrome_test.tar.bz2',
+                  'dep-perf_data_dep.tar.bz2']
 
 # Sets up global to share between classes.
 updater = None
@@ -453,6 +454,9 @@
       # Copy over the required deps tar balls to the telemetry directory.
       for dep in TELEMETRY_DEPS:
         dep_path = os.path.join(deps_path, dep)
+        if not os.path.exists(dep_path):
+          # This dep does not exist (could be new), do not extract it.
+          continue
         try:
           common_util.ExtractTarball(dep_path, telemetry_path)
         except common_util.CommonUtilError as e: