Roll src/third_party/skia e08b443f9bda..b520476ee6dc (5 commits) (#9392)

https://skia.googlesource.com/skia.git
/%2Blog/e08b443f9bda..b520476ee6dc

git log e08b443f9bda453c016d0cc4f73ad93352d539f3..b520476ee6dcde51054d14c183c8e2c12c7602f5 --date=short --no-merges --format=%ad %ae %s
2019-06-19 robertphillips@google.com Swap GrSurfaceProxy over to being held via sk_sp
2019-06-20 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 88e0322122f2..c5c937e1e8bd (5 commits)
2019-06-20 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update Go deps
2019-06-20 skia-autoroll@skia-public.iam.gserviceaccount.com Roll ../src a69f99029b91..8f8d2c8d5447 (406 commits)
2019-06-20 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 62bb5edfe0a6..4aa4fcd61334 (5 commits)

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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 (bsalomon@google.com), and stop
the roller if necessary.

DEPS

@@ -24,7 +24,7 @@ vars = {
   'fuchsia_git': 'https://fuchsia.googlesource.com',
   'github_git': 'https://github.com',
   'skia_git': 'https://skia.googlesource.com',
-  'skia_revision': 'e08b443f9bda453c016d0cc4f73ad93352d539f3',
+  'skia_revision': 'b520476ee6dcde51054d14c183c8e2c12c7602f5',
 
   # When updating the Dart revision, ensure that all entries that are
   # dependencies of Dart are also updated to match the entries in the

ci/licenses_golden/licenses_skia

-Signature: 40d36e9ee02f216a10dc319d593e01a6
+Signature: e9147d32b18197c5ff84bda8d756365b
 
 UNUSED LICENSES:
 
@@ -1553,7 +1553,6 @@ FILE: ../../../third_party/skia/src/gpu/GrFPArgs.h
 FILE: ../../../third_party/skia/src/gpu/GrLegacyDirectContext.cpp
 FILE: ../../../third_party/skia/src/gpu/GrProxyProvider.cpp
 FILE: ../../../third_party/skia/src/gpu/GrProxyProvider.h
-FILE: ../../../third_party/skia/src/gpu/GrProxyRef.h
 FILE: ../../../third_party/skia/src/gpu/GrRenderTargetProxyPriv.h
 FILE: ../../../third_party/skia/src/gpu/GrResourceProviderPriv.h
 FILE: ../../../third_party/skia/src/gpu/ccpr/GrCCClipPath.cpp