Fix test crashes related to AccountManagerHelper.

chrome/android/javatests/src/org/chromium/chrome/browser/test/CommandLineInitRule.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/test/CommandLineInitRule.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/test/CommandLineInitRule.java b/chrome/android/javatests/src/org/chromium/chrome/browser/test/CommandLineInitRule.java
new file mode 100644
index 0000000000000000000000000000000000000000..979e2b6b3a0c232cab536fe42ccbb0f235532560
--- /dev/null
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/test/CommandLineInitRule.java
@@ -0,0 +1,39 @@
+// Copyright 2017 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.chrome.browser.test;
+
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+import org.chromium.base.CommandLine;
+
+import java.util.Arrays;
+
+/**
+ * JUnit rule for setting command line arguments before initializing the browser.
+ *
+ * Having it as its own rule allows us to chain it using RuleChain and allows it to be explicitly
+ * run prior to initializing the browser.
+ */
+public class CommandLineInitRule implements TestRule {
+    private String[] mArgs;
+
+    public CommandLineInitRule(String[] args) {
+        if (args != null) {
+            mArgs = Arrays.copyOf(args, args.length);
+        }
+    }
+
+    @Override
+    public Statement apply(Statement base, Description description) {
+        return new Statement() {
+            @Override
+            public void evaluate() {
+                CommandLine.init(mArgs);
+            }
+        };
+    }
+}