Tiger viewer upload script now downloads missing caspian files

If the caspian files are missing, the upload script will now download
them from the current latest deployment before uploading the new
version. This allows a chrome dev to upload a new version without
worrying about caspian if their changes are unrelated.

Change-Id: Ib0f79f760845b239215e2c8f8be3c964060fbeb4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2551775Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829632}

tools/binary_size/libsupersize/upload_html_viewer.py

@@ -7,6 +7,7 @@
 
 import argparse
 import os
+import requests
 import shutil
 import subprocess
 import sys
@@ -15,6 +16,12 @@ import uuid
 
 
 FIREBASE_PROJECT = 'chrome-supersize'
+PROD_URL = 'https://chrome-supersize.firebaseapp.com/'
+CASPIAN_FILES = [
+    'caspian_web.js',
+    'caspian_web.wasm',
+    'caspian_web.wasm.map',
+]
 
 PROD = 'prod'
 STAGING = 'staging'
@@ -72,12 +79,22 @@ def _FirebaseDeploy(project_dir, deploy_mode=PROD):
                           cwd=project_dir)
 
 
+def _DownloadCaspianFiles(project_static_dir):
+  for f in CASPIAN_FILES:
+    response = requests.get(PROD_URL + f)
+    with open(os.path.join(project_static_dir, f), 'wb') as output:
+      output.write(response.content)
+
+
 def _CopyStaticFiles(project_static_dir):
   """Copy over static files from the static directory."""
   static_files = os.path.join(os.path.dirname(__file__), 'static')
-  if not os.path.exists(os.path.join(static_files, 'caspian_web.js')):
-    raise Exception('static/caspian_web.js is missing. See caspian/README.md')
   shutil.copytree(static_files, project_static_dir)
+  if not all(
+      os.path.exists(os.path.join(static_files, f)) for f in CASPIAN_FILES):
+    print('Some caspian files do not exist in ({}). Downloading *all* caspian '
+          'files from currently deployed instance.'.format(static_files))
+    _DownloadCaspianFiles(project_static_dir)
 
 
 def _FillInAndCopyTemplates(project_static_dir):