[Android] Incorporate findbugs into android builds.

build/config/android/internal_rules.gni

Index: build/config/android/internal_rules.gni
diff --git a/build/config/android/internal_rules.gni b/build/config/android/internal_rules.gni
index 8920e95abccd1509fa67b70ac27c73ea6c83c701..3068fcdda9e60db6eadcc72b4684f41ba9e32cce 100644
--- a/build/config/android/internal_rules.gni
+++ b/build/config/android/internal_rules.gni
@@ -62,6 +62,41 @@ template("android_lint") {
   }
 }
 
+template("findbugs") {
+  jar_path = invoker.jar_path
+
+  build_config = invoker.build_config
+
+  action(target_name) {
+    script = "//build/android/findbugs_diff.py"
+    depfile = "$target_gen_dir/$target_name.d"
+    result_path = "$target_gen_dir/$target_name/result.xml"
+    exclusions_file = "//build/android/findbugs_filter/findbugs_exclude.xml"
+
+    rebased_build_config = rebase_path(build_config, root_build_dir)
+
+    inputs = [
+      "//build/android/pylib/utils/findbugs.py",
+      exclusions_file,
+      jar_path,
+    ]
+
+    outputs = [
+      result_path,
+    ]
+
+    args = [
+      "--depfile",
+      rebase_path(depfile, root_build_dir),
+      "--auxclasspath-gyp",
+      "@FileArg($rebased_build_config:javac:classpath)",
+      "--output-file",
+      rebase_path(result_path, root_build_dir),
+      rebase_path(jar_path, root_build_dir),
+    ]
+  }
+}
+
 template("dex") {
   set_sources_assignment_filter([])
   if (defined(invoker.testonly)) {