Merge to XFA: Make standalone PDFium DEPS pull clang-format.

DEPS

 deps = {
   "build/gyp":
     "https://chromium.googlesource.com/external/gyp",
 
   "buildtools":
     "https://chromium.googlesource.com/chromium/buildtools.git@46ce8cb60364e9e0b21a81136c7debdddfd063a8",
 
   "testing/corpus":
      "https://pdfium.googlesource.com/pdfium_tests@4b9a1d593e5a101d034a4f1195174a22c179a42d",
 
@@ skipping 24 matching lines @@
   '+v8',
 ]
 
 hooks = [
   {
     # A change to a .gyp, .gypi, or to GYP itself should run the generator.
     'name': 'gyp',
     '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',
+    ],
+  },
+]