[DO NOT MERGE] Add RBE mk file to support bootstrapping RBE and setting relevant

environment variables.

Test: Built aosp_arm-user with and without USE_RBE. With USE_RBE,
used a simple proxy script in place of rewrapper.

Bug: b/166182389
Change-Id: Ifb6bfd9f7292346f4750a6a409aa0def4e3c0363
Merged-In: Ifb6bfd9f7292346f4750a6a409aa0def4e3c0363

core/config.mk

@@ -304,6 +304,7 @@ endef
 ifeq ($(CALLED_FROM_SETUP),true)
 include $(BUILD_SYSTEM)/ccache.mk
 include $(BUILD_SYSTEM)/goma.mk
+include $(BUILD_SYSTEM)/rbe.mk
 endif
 
 ifdef TARGET_PREFER_32_BIT

core/rbe.mk

@@ -0,0 +1,32 @@
+#
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+# Notice: this works only with Google's RBE service.
+ifneq ($(filter-out false,$(USE_RBE)),)
+  ifdef RBE_DIR
+    rbe_dir := $(RBE_DIR)
+  else
+    rbe_dir := $(HOME)/rbe
+  endif
+  RBE_WRAPPER := $(rbe_dir)/rewrapper
+
+  # Append rewrapper to existing *_WRAPPER variables so it's possible to
+  # use both ccache and rewrapper.
+  CC_WRAPPER := $(strip $(CC_WRAPPER) $(RBE_WRAPPER))
+  CXX_WRAPPER := $(strip $(CXX_WRAPPER) $(RBE_WRAPPER))
+
+  rbe_dir :=
+endif

core/soong_config.mk

@@ -139,6 +139,7 @@ $(call add_json_str,  ProductServicesPath,               $(TARGET_COPY_OUT_PRODU
 $(call add_json_bool, MinimizeJavaDebugInfo,             $(filter true,$(PRODUCT_MINIMIZE_JAVA_DEBUG_INFO)))
 
 $(call add_json_bool, UseGoma,                           $(filter-out false,$(USE_GOMA)))
+$(call add_json_bool, UseRBE,                            $(filter-out false,$(USE_RBE)))
 $(call add_json_bool, Arc,                               $(filter true,$(TARGET_ARC)))
 
 $(call add_json_list, NamespacesToExport,                $(PRODUCT_SOONG_NAMESPACES))