Move an #include out of a namespace.
Move an #include out of a namespace.

This is required to build Chromium's ui_base target with -fmodules, but it
seems like a good change regardless.  Including a header in a namespace is
weird.

BUG=chromium:543704

Review URL: https://codereview.chromium.org/1398843007

HalCanary/skia-hc,tmpvar/skia.cc,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,google/skia,qrealka/skia-hc,Hikari-no-Tenshi/android_external_skia,qrealka/skia-hc,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,rubenvb/skia,tmpvar/skia.cc,qrealka/skia-hc,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,tmpvar/skia.cc,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,google/skia,aosp-mirror/platform_external_skia,tmpvar/skia.cc,rubenvb/skia,rubenvb/skia,HalCanary/skia-hc,HalCanary/skia-hc,HalCanary/skia-hc,google/skia,Hikari-no-Tenshi/android_external_skia,google/skia,rubenvb/skia,rubenvb/skia,qrealka/skia-hc,qrealka/skia-hc,qrealka/skia-hc,HalCanary/skia-hc,rubenvb/skia,HalCanary/skia-hc,google/skia,HalCanary/skia-hc,rubenvb/skia,aosp-mirror/platform_external_skia,rubenvb/skia,aosp-mirror/platform_external_skia,tmpvar/skia.cc,aosp-mirror/platform_external_skia,tmpvar/skia.cc,google/skia,tmpvar/skia.cc,tmpvar/skia.cc,qrealka/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,Hikari-no-Tenshi/android_external_skia,aosp-mirror/platform_external_skia,tmpvar/skia.cc,rubenvb/skia,HalCanary/skia-hc,Hikari-no-Tenshi/android_external_skia,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,rubenvb/skia,qrealka/skia-hc