Drop unneeded .get() in GrCoverageCountingPathRenderer.cpp
Drop unneeded .get() in GrCoverageCountingPathRenderer.cpp

MSVC's std::unique_ptr<>::get() is marked as NODISCARD, and the .get()
call here causes a warning.

Bug: chromium:752720
Change-Id: Iadc217247533b6148285f7a81c982527d98c86f9
Reviewed-on: https://skia-review.googlesource.com/130360
Reviewed-by: Robert Phillips <95e8ac5504948c7bf91b22c16a8dbb7ae7c66bfd@google.com>
Commit-Queue: Robert Phillips <95e8ac5504948c7bf91b22c16a8dbb7ae7c66bfd@google.com>

aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,Hikari-no-Tenshi/android_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,google/skia,google/skia,rubenvb/skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,google/skia,HalCanary/skia-hc,HalCanary/skia-hc,HalCanary/skia-hc,rubenvb/skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,HalCanary/skia-hc,HalCanary/skia-hc,rubenvb/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,google/skia,google/skia,rubenvb/skia,google/skia,google/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,rubenvb/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,rubenvb/skia,HalCanary/skia-hc,rubenvb/skia