android: Use use_goma=1 gomadir gyp defines instead of magic GOMA_DIR env var.

build/toolchain/goma.gni

Index: build/toolchain/goma.gni
diff --git a/build/toolchain/goma.gni b/build/toolchain/goma.gni
index 66348a96fce2de38b34ddcd8b976ed3a1d0b5230..dca6a4dbfaaf87b94038d27cae39ad237e0f0a06 100644
--- a/build/toolchain/goma.gni
+++ b/build/toolchain/goma.gni
@@ -6,9 +6,6 @@
 #
 # This is currently designed to match the GYP build exactly, so as not to break
 # people during the transition.
-#
-# TODO(brettw) make Android work like normal Linux. It's silly that Android has
-# completely different logic for configuring Goma.
 
 declare_args() {
   use_goma = false
@@ -16,18 +13,6 @@ declare_args() {
   goma_dir = ""
 }
 
-# The Android GYP build has some logic that automatically turns on goma when
-# the directory is set, but this isn't done for other platforms.
-# TODO(brettw) rationalize all Linux-y platforms.
-if (is_android) {
-  if (goma_dir == "") {
-    goma_dir = exec_script("android/default_goma_for_android.py", [], "value")
-  }
-  if (goma_dir != "") {
-    use_goma = true
-  }
-}
-
 if (use_goma && goma_dir == "") {
   # Set the default goma directory. This must be a character-for-character
   # match for the GYP default or else the compilers for the different targets