Make goma work for the GN build on linux.

This drops the old gyp-compatible settings and wires up the
Linux and Android toolchains to be goma-aware. Mac and Win can
follow in subsequent CLs.

R=brettw@chromium.org, thakis@chromium.org
BUG=394501

Review URL: https://codereview.chromium.org/397173004

git-svn-id: http://src.chromium.org/svn/trunk/src/build@283971 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

toolchain/goma.gni

@@ -20,12 +20,3 @@ declare_args() {
     goma_dir = getenv("HOME") + "/goma"
   }
 }
-
-if (use_goma) {
-  # Define the toolchain for the GYP build when using goma.
-  make_goma_global_settings =
-    "['CC_wrapper', '$goma_dir/gomacc']," +
-    "['CXX_wrapper', '$goma_dir/gomacc']," +
-    "['CC.host_wrapper', '$goma_dir/gomacc']," +
-    "['CXX.host_wrapper', '$goma_dir/gomacc'],"
-}

toolchain/linux/BUILD.gn

@@ -7,9 +7,16 @@ import("//build/toolchain/clang.gni")
 import("//build/toolchain/gcc_toolchain.gni")
 import("//build/toolchain/goma.gni")
 
+if (use_goma) {
+  goma_prefix = "$goma_dir/gomacc "
+} else {
+  goma_prefix = ""
+}
+
 gcc_toolchain("arm") {
-  cc = "arm-linux-gnueabi-gcc"
-  cxx = "arm-linux-gnueabi-g++"
+  cc = "${goma_prefix}arm-linux-gnueabi-gcc"
+  cxx = "${goma_prefix}arm-linux-gnueabi-g++"
+
   ar = "arm-linux-gnueabi-ar"
   ld = cxx
 
@@ -26,8 +33,8 @@ gcc_toolchain("clang_x86") {
     prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                          root_build_dir)
   }
-  cc = "$prefix/clang"
-  cxx = "$prefix/clang++"
+  cc = "${goma_prefix}$prefix/clang"
+  cxx = "${goma_prefix}$prefix/clang++"
 
   ar = "ar"
   ld = cxx
@@ -38,8 +45,8 @@ gcc_toolchain("clang_x86") {
 }
 
 gcc_toolchain("x86") {
-  cc = "gcc"
-  cxx = "g++"
+  cc = "${goma_prefix}gcc"
+  cxx = "$goma_prefix}g++"
 
   ar = "ar"
   ld = cxx
@@ -57,8 +64,8 @@ gcc_toolchain("clang_x64") {
     prefix = rebase_path("//third_party/llvm-build/Release+Asserts/bin",
                          root_build_dir)
   }
-  cc = "$prefix/clang"
-  cxx = "$prefix/clang++"
+  cc = "${goma_prefix}$prefix/clang"
+  cxx = "${goma_prefix}$prefix/clang++"
 
   ar = "ar"
   ld = cxx
@@ -69,8 +76,8 @@ gcc_toolchain("clang_x64") {
 }
 
 gcc_toolchain("x64") {
-  cc = "gcc"
-  cxx = "g++"
+  cc = "${goma_prefix}gcc"
+  cxx = "${goma_prefix}g++"
 
   ar = "ar"
   ld = cxx