Roll src/third_party/skia 1179d5dfaf8d..b7b2da871e95 (1 commits) (#7996)

https://skia.googlesource.com/skia.git/%2Blog/1179d5dfaf8d..b7b2da871e95

git log 1179d5dfaf8d0a2a7c6c8f7e997dd267b118d5db..b7b2da871e959ce9d412498b0378f5ace0dd5808 --date=short --no-merges --format=%ad %ae %s
2019-02-28 mtklein@google.com set -fcolor-diagnostics when is_clang

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Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff (scroggo@google.com), and stop
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DEPS

@@ -23,7 +23,7 @@ vars = {
   'fuchsia_git': 'https://fuchsia.googlesource.com',
   'github_git': 'https://github.com',
   'skia_git': 'https://skia.googlesource.com',
-  'skia_revision': '1179d5dfaf8d0a2a7c6c8f7e997dd267b118d5db',
+  'skia_revision': 'b7b2da871e959ce9d412498b0378f5ace0dd5808',
 
   # When updating the Dart revision, ensure that all entries that are
   # dependencies of Dart are also updated to match the entries in the