Refactor how we fetch Telemetry deps conditionally

DEPS

Index: DEPS
diff --git a/DEPS b/DEPS
index cc154a5b955daad38bf6d7cfd2129fbbdf1543a6..b6db1abca65736dad43d6e5cf25b31f4e44f5acb 100644
--- a/DEPS
+++ b/DEPS
@@ -890,10 +890,23 @@ hooks = [
     'name': 'fetch_telemetry_binary_dependencies',
     'pattern': '.',
     'action': [ 'python',
+                'tools/perf/conditionally_execute'
+                '--gyp-condition', 'fetch_telemetry_dependencies=1',

[nednguyen, 2017/06/05 21:31:47]

With this, we can remove the conditioning code in
https://github.com/catapult-project/catapult/blob/master/telemetry/bin/fetch_...

                 'src/third_party/catapult/telemetry/bin/fetch_telemetry_binary_dependencies',
     ],
   },
 
+  # Download all WPR archives in tools/perf/
+  {
+    'name': 'fetch_perf_wpr_archives',
+    'pattern': '.',
+    'action': [ 'python',
+                'tools/perf/conditionally_execute'
+                '--gyp-condition', 'fetch_telemetry_dependencies=1',
+                'tools/perf/fetch_benchmark_deps.py', '--force'
+    ],
+  },
+
   # Download checkstyle for use in PRESUBMIT for Java changes.
   # TODO(jbudorick): Move this back down to the android section of hooks_os
   # once it's no longer necessary for the chromium_presubmit bot.