Reland "Enable non-standalone builds with dawn"

This reverts commit 122f1b9.

Reason for revert: unrelated to G3 failure?

Original change's description:
> Revert "Enable non-standalone builds with dawn"
>
> This reverts commit 25deba3.
>
> Reason for revert: Possible Google3 roll break
>
> Original change's description:
> > Enable non-standalone builds with dawn
> >
> > Bug: skia:12276
> > Change-Id: Iaf7311fef43bd9c37bfc7b7a6221f6bea25f196d
> > Reviewed-on: https://skia-review.googlesource.com/c/skia/+/433696
> > Auto-Submit: Safa Sofuoglu <safasofuoglu@gmail.com>
> > Reviewed-by: Brian Salomon <bsalomon@google.com>
> > Reviewed-by: Stephen White <senorblanco@google.com>
> > Commit-Queue: Brian Salomon <bsalomon@google.com>
>
> TBR=bsalomon@google.com,senorblanco@google.com,skcq-be@skia-corp.google.com.iam.gserviceaccount.com,safasofuoglu@gmail.com
>
> Change-Id: I05dc7e1107ae08d4c9d4a7663704eb14f711208d
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: skia:12276
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/471757
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Commit-Queue: Julia Lavrova <jlavrova@google.com>

# Not skipping CQ checks because this is a reland.

Bug: skia:12276
Change-Id: Ifca6eaba59083afef4bb7a1ee73de1b8538b383b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/471761
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

Author: bsalomon

AUTHORS

@@ -46,6 +46,7 @@ Opera Software ASA <*@opera.com>
 Pavel Krajcevski <pavel@cs.unc.edu>
 Petar Kirov <petar.p.kirov@gmail.com>
 Raul Tambre <raul@tambre.ee>
+Safa Sofuoglu <safasofuoglu@gmail.com>
 Samsung <*@samsung.com>
 Samsung Open Source Group <*@osg.samsung.com>
 Sergey Melnikov <Melnikov.Sergey.V@gmail.com>

BUILD.gn

@@ -14,7 +14,7 @@ if (is_fuchsia) {
 }
 
 if (skia_use_dawn) {
-  import("third_party/externals/dawn/scripts/dawn_features.gni")
+  import("//third_party/externals/dawn/scripts/dawn_features.gni")
 }
 
 if (defined(skia_settings)) {
@@ -928,8 +928,11 @@ optional("gpu") {
     deps += [
       "//third_party/externals/dawn/src/dawn:dawn_proc",
       "//third_party/externals/dawn/src/dawn:dawncpp",
-      "//third_party/externals/dawn/src/dawn_native",
     ]
+    if (dawn_enable_d3d12 || dawn_enable_desktop_gl || dawn_enable_metal ||
+        dawn_enable_opengles || dawn_enable_vulkan) {
+      deps += [ "//third_party/externals/dawn/src/dawn_native" ]
+    }
     if (dawn_enable_d3d12) {
       libs += [
         "d3d12.lib",