Use the Errorprone Compiler

build/java.gypi

Index: build/java.gypi
diff --git a/build/java.gypi b/build/java.gypi
index 716eb34beacc735d95e9fa43c756911a812433f8..255dca91ee94fd84da26c64e6f165f217b3f694d 100644
--- a/build/java.gypi
+++ b/build/java.gypi
@@ -82,6 +82,8 @@
     'run_findbugs%': 0,
     'proguard_config%': '',
     'proguard_preprocess%': '0',
+    'enable_errorprone%': '0',
+    'errorprone_exe_path': '<(PRODUCT_DIR)/bin.java/chromium_errorprone',
     'variables': {
       'variables': {
         'proguard_preprocess%': 0,
@@ -256,6 +258,14 @@
       'variables': {
         'java_sources': ['>!@(find >(java_in_dir)/src >(additional_src_dirs) -name "*.java")'],
       },
+      'conditions': [
+        ['enable_errorprone == 1', {
+          'extra_inputs': [
+            '<(errorprone_exe_path)',
+          ],
+          'extra_args': [ '--use-errorprone-path=<(errorprone_exe_path)' ],
+        }],
+      ],
       'inputs': [
         '<(DEPTH)/build/android/gyp/util/build_utils.py',
         '<(DEPTH)/build/android/gyp/javac.py',