Cleanup resource flags

Converts GrResourceProvider::Flags and GrResourceCache::ScratchFlags
to "enum class" and fixes a case where we were accidentally using the
wrong type of flag. Makes sure to allocate GrSWMaskHelper proxies with
kNoPendingIO.

Bug: skia:8351
Change-Id: Ibcaa26314a53d0cb31ae22915ab94ab0fc07e76d
Reviewed-on: https://skia-review.googlesource.com/157280
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/tests/GrMeshTest.cpp b/tests/GrMeshTest.cpp
index 3997dc4..762430f 100644
--- a/tests/GrMeshTest.cpp
+++ b/tests/GrMeshTest.cpp
@@ -378,8 +378,8 @@
     return sk_sp<const GrBuffer>(
         fState->resourceProvider()->createBuffer(
             count * sizeof(T), kVertex_GrBufferType, kDynamic_GrAccessPattern,
-            GrResourceProvider::kNoPendingIO_Flag |
-            GrResourceProvider::kRequireGpuMemory_Flag, data));
+            GrResourceProvider::Flags::kNoPendingIO |
+            GrResourceProvider::Flags::kRequireGpuMemory, data));
 }
 
 sk_sp<const GrBuffer> DrawMeshHelper::getIndexBuffer() {