Make standalone PDFium DEPS pull clang-format.

DEPS

Index: DEPS
diff --git a/DEPS b/DEPS
index 67b57aaf62446d1261e15fd27609292e2e0abb9d..ee9df7e8615e6af2da7298c9e859fa07d869bf10 100644
--- a/DEPS
+++ b/DEPS
@@ -44,4 +44,38 @@ hooks = [
     'pattern': '.',
     'action': ['python', 'build/gyp_pdfium'],
   },
-]
+  # Pull clang-format binaries using checked-in hashes.
+  {
+    'name': 'clang_format_win',
+    'pattern': '.',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=win32',
+                '--no_auth',
+                '--bucket', 'chromium-clang-format',
+                '-s', 'buildtools/win/clang-format.exe.sha1',
+    ],
+  },
+  {
+    'name': 'clang_format_mac',
+    'pattern': '.',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=darwin',
+                '--no_auth',
+                '--bucket', 'chromium-clang-format',
+                '-s', 'buildtools/mac/clang-format.sha1',
+    ],
+  },
+  {
+    'name': 'clang_format_linux',
+    'pattern': '.',
+    'action': [ 'download_from_google_storage',
+                '--no_resume',
+                '--platform=linux*',
+                '--no_auth',
+                '--bucket', 'chromium-clang-format',
+                '-s', 'buildtools/linux64/clang-format.sha1',
+    ],
+  },
+]