Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/c8fbe98..9004761

TBR=machenbach@chromium.org,hablich@chromium.org,sergiyb@chromium.org

Change-Id: I1943b52306afc8095b08a15ed94b7d1d43eeaae4
Reviewed-on: https://chromium-review.googlesource.com/981498Reviewed-by: v8 autoroll <v8-autoroll@chromium.org>
Commit-Queue: v8 autoroll <v8-autoroll@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52235}

DEPS

@@ -13,7 +13,7 @@ vars = {
 
 deps = {
   'v8/build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'c8fbe98ef927f18224923231c6bcd0fd4532de2b',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '900476133d79556d80d780c2427eb857f5f7fe80',
   'v8/tools/gyp':
     Var('chromium_url') + '/external/gyp.git' + '@' + 'd61a9397e668fa9843c4aa7da9e79460fe590bfb',
   'v8/third_party/icu':