Export include directories to dependents in GN.
Export include directories to dependents in GN.

Translator headers that are included by dependent code
(example: ShaderLang.h) expect to be able to include files from
"includes" (example: "KHR/khrplatform.h"). This automatically
applies this include path to dependent targets.

Change-Id: I6990f66132562f142a6cdf8b8c434d2dbaad1c98
Reviewed-on: https://chromium-review.googlesource.com/209452
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Tested-by: Brett Wilson <fb88c5421e7dc886db1d0953e53631b4de4e3e86@chromium.org>
Reviewed-by: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>

ppy/angle,mybios/angle,ecoal95/angle,nandhanurrevanth/angle,android-ia/platform_external_chromium_org_third_party_angle,xin3liang/platform_external_chromium_org_third_party_angle,xin3liang/platform_external_chromium_org_third_party_angle,crezefire/angle,domokit/waterfall,android-ia/platform_external_chromium_org_third_party_angle,larsbergstrom/angle,csa7mdm/angle,ghostoy/angle,csa7mdm/angle,ppy/angle,jgcaaprom/android_external_chromium_org_third_party_angle,ecoal95/angle,vvuk/angle,ppy/angle,larsbergstrom/angle,ppy/angle,mikolalysenko/angle,mrobinson/rust-angle,mrobinson/rust-angle,ecoal95/angle,mikolalysenko/angle,nandhanurrevanth/angle,MIPS/external-chromium_org-third_party-angle,android-ia/platform_external_chromium_org_third_party_angle,mybios/angle,bsergean/angle,mlfarrell/angle,jgcaaprom/android_external_chromium_org_third_party_angle,bsergean/angle,bsergean/angle,MSOpenTech/angle,ghostoy/angle,csa7mdm/angle,mrobinson/rust-angle,mlfarrell/angle,xin3liang/platform_external_chromium_org_third_party_angle,domokit/waterfall,mlfarrell/angle,nandhanurrevanth/angle,mybios/angle,jgcaaprom/android_external_chromium_org_third_party_angle,vvuk/angle,mlfarrell/angle,ghostoy/angle,xin3liang/platform_external_chromium_org_third_party_angle,crezefire/angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,android-ia/platform_external_chromium_org_third_party_angle,vvuk/angle,MSOpenTech/angle,ecoal95/angle,mrobinson/rust-angle,nandhanurrevanth/angle,MIPS/external-chromium_org-third_party-angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,larsbergstrom/angle,larsbergstrom/angle,mikolalysenko/angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,ghostoy/angle,MSOpenTech/angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,csa7mdm/angle,crezefire/angle,ecoal95/angle,bsergean/angle,vvuk/angle,MIPS/external-chromium_org-third_party-angle,MSOpenTech/angle,crezefire/angle,mybios/angle,mrobinson/rust-angle,MIPS/external-chromium_org-third_party-angle,jgcaaprom/android_external_chromium_org_third_party_angle,mikolalysenko/angle