Add errorprone into third_party

third_party/errorprone/src/org/chromium/errorprone/ChromiumErrorProneCompiler.java

Index: third_party/errorprone/src/org/chromium/errorprone/ChromiumErrorProneCompiler.java
diff --git a/third_party/errorprone/src/org/chromium/errorprone/ChromiumErrorProneCompiler.java b/third_party/errorprone/src/org/chromium/errorprone/ChromiumErrorProneCompiler.java
new file mode 100644
index 0000000000000000000000000000000000000000..706c6412138c65b344d227ee84685c0b8ff8c48f
--- /dev/null
+++ b/third_party/errorprone/src/org/chromium/errorprone/ChromiumErrorProneCompiler.java
@@ -0,0 +1,57 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.errorprone;
+
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.ErrorProneOptions;
+import com.google.errorprone.ErrorProneScanner;
+import com.google.errorprone.ErrorReportingJavaCompiler;
+import com.google.errorprone.JDKCompatible;
+import com.google.errorprone.Scanner;
+import com.google.errorprone.bugpatterns.BugChecker;
+
+import com.sun.tools.javac.file.JavacFileManager;
+import com.sun.tools.javac.main.Main;
+import com.sun.tools.javac.util.Context;
+import com.sun.tools.javac.util.List;
+
+import java.io.PrintWriter;
+import java.util.HashSet;
+import java.util.Set;
+
+import javax.tools.JavaFileObject;
+
+/**
+ * Configures (and compiles with) the error-prone java compiler.
+ */
+public class ChromiumErrorProneCompiler {
+
+    public static void main(String[] args) {
+        System.exit(compile(args));
+    }
+
+    private static int compile(String[] args) {

[jbudorick, 2015/05/07 18:49:14]

Why are we creating our own wrapper executable? Is there no errorprone binary we
can call directly?

+        PrintWriter printWriter = new PrintWriter(System.err, true);
+        Main main = new Main("javac (chromium-error-prone)", printWriter);
+        Context context = new Context();
+        JavacFileManager.preRegister(context);
+
+        ErrorProneOptions epOptions = ErrorProneOptions.processArgs(args);
+        final Set<String> disabledChecks = new HashSet<String>(epOptions.getDisabledChecks());
+
+        Scanner scannerInContext = new ErrorProneScanner(new ErrorProneScanner.EnabledPredicate() {
+            @Override
+            public boolean isEnabled(Class<? extends BugChecker> check, BugPattern annotation) {
+                return !disabledChecks.contains(check.getCanonicalName());
+            }
+        });
+        context.put(Scanner.class, scannerInContext);
+
+        ErrorReportingJavaCompiler.preRegister(context);
+        return JDKCompatible.runCompile(
+                main, epOptions.getRemainingArgs(), context, List.<JavaFileObject>nil(), null);
+    }
+
+}