Allow WebRTC to require Mac 10.7 deployments in GN builds.

build_overrides/README.md

Index: build_overrides/README.md
diff --git a/build_overrides/README.md b/build_overrides/README.md
index d26312c9325ddcc3126ade50802a6cf879454cb1..fa12384341401402bc43a17171b52797fa1f3f0f 100644
--- a/build_overrides/README.md
+++ b/build_overrides/README.md
@@ -18,3 +18,12 @@ create its own build_overrides/v8.gni file, and in it set
 
 The two files should define the same set of variables, but the values can
 vary as appropriate to the needs of the two different builds.
+
+The build.gni file provides a way for projects to override defaults for
+variables used in //build itself (which we want to be shareable between
+projects).
+
+TODO(crbug.com/588513): Ideally //build_overrides and, in particular,
+//build_overrides.gni should go away completely in favor of some mechanism

[kjellander_chromium, 2016/02/22 04:18:40]

I guess you mean //build_overrides/build.gni here? Although having the file in
the root may make more sense, since now the idea is that the build_overrides
directory won't have other more files, right?

[Dirk Pranke, 2016/02/22 04:25:04]

Good catch, I meant //build_overrides/build.gni  on line 27.

The idea is that we stuff all of the build overrides into the already-existing
.gn file, and so we don't need a separate overrides directory (for either
//build overrrides or overrides to other projects like v8 or webrtc).

Of course, the design is still TBD.

+that can re-use other required files like //.gn, so that we don't have
+to keep requiring projects to create a bunch of different files to use GN.