Make the GN Android builds goma-aware.

build/toolchain/android/BUILD.gn

Index: build/toolchain/android/BUILD.gn
diff --git a/build/toolchain/android/BUILD.gn b/build/toolchain/android/BUILD.gn
index dc3bfeddab776e9bdfe9da5358d7e68599319f4b..b483e214df682cd56d5151d7779d0dad2dea6a96 100644
--- a/build/toolchain/android/BUILD.gn
+++ b/build/toolchain/android/BUILD.gn
@@ -32,8 +32,14 @@ template("android_gcc_toolchain") {
     # The tools should be run relative to the build dir.
     tool_prefix = rebase_path(invoker.tool_prefix, root_build_dir)
 
-    cc = tool_prefix + "gcc"
-    cxx = tool_prefix + "g++"
+    if (use_goma) {

[brettw, 2014/07/22 17:20:22]

This narrower scoping is better anyway.

+      goma_prefix = "$goma_dir/gomacc "
+    } else {
+      goma_prefix = ""
+    }
+
+    cc = goma_prefix + tool_prefix + "gcc"
+    cxx = goma_prefix + tool_prefix + "g++"
     ar = tool_prefix + "ar"
     ld = cxx