Add SwiftShader to DEPS.
Add SwiftShader to DEPS.

Bug: skia:7671
No-Try: true
Change-Id: Ib41428b5c3ed8d6655fac38e525014663ce85817
Reviewed-on: https://skia-review.googlesource.com/121357
Commit-Queue: Hal Canary <fd9641b23487c8ee78406c27513624c460600766@google.com>
Auto-Submit: Ben Wagner <3ef7217be91069877d94f7907ce5479000772cd3@google.com>
Reviewed-by: Hal Canary <fd9641b23487c8ee78406c27513624c460600766@google.com>

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