Add the ability to customize skia's settings in gn

Fuchsia also builds Skia for host and wants to set various gn variables (e.g.,
skia_enable_flutter_defines) when is_linux is true. Rather than teach Skia
about all these permutations, this CL adds a skia_settings variable that can be
used by clients to customize Skia's configuration.

Change-Id: I6fd4798b0ce86615688ea19328236ae0f3a93c4d
Reviewed-on: https://skia-review.googlesource.com/59720
Commit-Queue: Adam Barth <abarth@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 0d99236781..33922d708d 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -75,6 +75,10 @@ declare_args() {
   }
 }
 
+if (defined(skia_settings)) {
+  import(skia_settings)
+}
+
 # Our tools require static linking (they use non-exported symbols).
 skia_enable_tools = skia_enable_tools && !is_component_build