Move error_prone config to external/error_prone

The error_prone config will likely need to be updated at the same
time as the error_prone prebuilts, so move the config into the same
project.  This requires jumping through some hoops because
external/error_prone may not be present in all manifests.

Bug: 64489631
Test: m -j RUN_ERROR_PRONE=true
Change-Id: I2c59df1148134ffedac0e00d32ac7082a9fb5330

java/config/error_prone.go

@@ -0,0 +1,45 @@
+// Copyright 2017 Google Inc. All rights reserved.
+//
+// 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.
+
+package config
+
+var (
+	// These will be filled out by external/error_prone/soong/error_prone.go if it is available
+	ErrorProneJavacJar    string
+	ErrorProneJar         string
+	ErrorProneClasspath   string
+	ErrorProneChecksError string
+	ErrorProneFlags       string
+)
+
+// Wrapper that grabs value of val late so it can be initialized by a later module's init function
+func errorProneVar(name string, val *string) {
+	pctx.VariableFunc(name, func(config interface{}) (string, error) {
+		return *val, nil
+	})
+}
+
+func init() {
+	errorProneVar("ErrorProneJar", &ErrorProneJar)
+	errorProneVar("ErrorProneJavacJar", &ErrorProneJavacJar)
+	errorProneVar("ErrorProneClasspath", &ErrorProneClasspath)
+	errorProneVar("ErrorProneChecksError", &ErrorProneChecksError)
+	errorProneVar("ErrorProneFlags", &ErrorProneFlags)
+
+	pctx.StaticVariable("ErrorProneCmd",
+		"${JavaCmd} -Xmx${JavacHeapSize} -Xbootclasspath/p:${ErrorProneJavacJar} "+
+			"-cp ${ErrorProneJar}:${ErrorProneClasspath} "+
+			"${ErrorProneFlags} ${CommonJdkFlags} ${ErrorProneChecksError}")
+
+}