Roll engine 58a1894..b952331 (16 commits)

flutter/engine@58a1894...b952331

git log 58a1894..b952331 --no-merges --oneline
b952331 Allow embedders to specify a custom GL proc address resolver. (flutter/engine#6204)
bf96dbe Revert "Some cleanups enabled by removing support for Dart. (flutter#5621)" (flutter/engine#6205)
3358115 Roll src/third_party/skia 094b3eaf479c..2810c856dfa2 (6 commits) (flutter/engine#6203)
4c2448d Some cleanups enabled by removing support for Dart. (flutter/engine#5621)
e27a2e9 Dart SDK roll for 2018/09/07 (flutter/engine#6201)
93dac2a Always save canvas and correctly pass antialias boolean in ClipRects. (flutter/engine#6199)
16c56af Roll src/third_party/skia 300b6197e344..094b3eaf479c (17 commits) (flutter/engine#6200)
2af72eb Don't map iOS reduce motion to disabled animations (flutter/engine#6194)
687cf08 Add option to invert paint colors to be used for smart invert accessibility on iOS (flutter/engine#6176)
85d47fb Accept file URIs as parameters in the RunInView service RPC (flutter/engine#6191)
5a19d76 Roll src/third_party/skia 0b80e62a14ae..300b6197e344 (9 commits) (flutter/engine#6198)
f33615c Roll src/third_party/skia b090b2b26803..0b80e62a14ae (2 commits) (flutter/engine#6197)
75f6bdf Revert "Dart SDK roll for 2018/09/06 (flutter#6189)" (flutter/engine#6192)
b09563b Roll src/third_party/skia 106d04e907c1..b090b2b26803 (1 commits) (flutter/engine#6193)
e164e83 Reset the raster cache when the compositor context is created. (flutter/engine#6150)
f02fc8c Dart SDK roll for 2018/09/06 (flutter/engine#6189)

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Author: engine-flutter-autoroll

bin/internal/engine.version

@@ -1 +1 @@
-58a1894a1cd798de2f9a206f157a90d45944028b
+b9523318caa1a99ffde8adaf331212eb879cabc9