Patch 2: Added a preprocessor flag for platform spellcheck.

build/config/BUILD.gn

Index: build/config/BUILD.gn
diff --git a/build/config/BUILD.gn b/build/config/BUILD.gn
index ba165ed9657a9a5e5314be1b4de67ee35c7cbe4f..287a1e762b52e84c1d114dca794af45e6a353e6c 100644
--- a/build/config/BUILD.gn
+++ b/build/config/BUILD.gn
@@ -80,6 +80,9 @@ config("feature_flags") {
   if (enable_spellcheck) {
     defines += [ "ENABLE_SPELLCHECK=1" ]
   }
+  if (use_platform_spellchecker) {

[cjhopman, 2015/07/08 22:29:30]

is use_platform_spellchecker already declared somewhere?

[dylanking, 2015/07/08 22:37:56]

I added it to build/common.gypi in this CL, is there somewhere else I need to
register it?

[cjhopman, 2015/07/08 22:43:36]

Yeah, you need to declare it in a gn file somewhere. Probably should go in
build/config/features.gni.

You have two options:
1. put it in the declare_args block (like safe_browsing_mode). If you do this,
then a user can configure the value directly with build arguments. Also, if a
comment precedes the declaration, that comment will be included in the output of
`gn args --list`.
2. put it outside the declare_args block (like enable_spellcheck). If you do
this, the value can only be changed by editing the file (well, or changing
things that the value depends on).

Do 2 if the value should just depend on other variables (like if it just depends
on the OS). Do 1 if certain platforms/configurations will support the feature
both on and off (this is particularly sometimes the case while changing a
platform from on to/from off).

[dylanking, 2015/07/08 23:30:21]

Done, hopefully correctly!

+    defines += [ "USE_PLATFORM_SPELLCHECKER=1" ]
+  }
   if (dont_embed_build_metadata) {
     defines += [ "DONT_EMBED_BUILD_METADATA" ]
   }