Roll src/third_party/dawn/ 391c8a922..63997221d (6 commits)

https://dawn.googlesource.com/dawn.git/+log/391c8a9224e5..63997221d7d8

$ git log 391c8a922..63997221d --date=short --no-merges --format='%ad %ae %s'
2018-11-20 cwallez Fix #include casing breaking linux->windows cross compilation
2018-11-20 cwallez Make codegen not cast between fnptrs.
2018-11-20 cwallez WireServer: Check for ID 0 in hand-written handlers.
2018-11-20 cwallez DawnWireAndFrontendFuzzer: skip SwapChainBuilderSetImplementation
2018-11-20 cwallez DawnWireAndFrontendFuzzer: don't leak the device.
2018-11-19 rharrison Tighten when signal trap is used in SPIRV-Cross fuzzers

Created with:
  roll-dep src/third_party/dawn

TBR=kainino@chromium.org

Bug=

Change-Id: I1aab57dfd4355edd8e11ab6a5e3e34ab4ea7f5bf
Reviewed-on: https://chromium-review.googlesource.com/c/1344138Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609746}

DEPS

@@ -236,7 +236,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling feed
   # and whatever else without interference from each other.
-  'dawn_revision': '391c8a9224e5bf02690722c06973af8427bdaa6b',
+  'dawn_revision': '63997221d7d880d8d1783abe326b90cd95cd92d2',
 }
 
 # Only these hosts are allowed for dependencies in this DEPS file.