Fix test crashes related to AccountManagerHelper.

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

Index: chrome/android/javatests/src/org/chromium/chrome/browser/test/ClearAppDataTestRule.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/test/ClearAppDataTestRule.java b/chrome/android/javatests/src/org/chromium/chrome/browser/test/ClearAppDataTestRule.java
index 2a3009a90cbfbdb0c1ca3ebff2d0a84be5858fbb..76e2e90b2d49948c2e9ead4a057b34dcc0783c96 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/test/ClearAppDataTestRule.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/test/ClearAppDataTestRule.java
@@ -4,7 +4,7 @@
 
 package org.chromium.chrome.browser.test;
 
-import android.content.Context;
+import android.support.test.InstrumentationRegistry;
 
 import org.junit.rules.TestRule;
 import org.junit.runner.Description;
@@ -18,18 +18,12 @@ import org.chromium.chrome.test.util.ApplicationData;
  * prior to launching the browser process.
  */
 public class ClearAppDataTestRule implements TestRule {
-    Context mContext;
-
-    public ClearAppDataTestRule(Context context) {
-        mContext = context;
-    }
-
     @Override
     public Statement apply(final Statement base, Description description) {
         return new Statement() {
             @Override
             public void evaluate() throws Throwable {
-                ApplicationData.clearAppData(mContext);
+                ApplicationData.clearAppData(InstrumentationRegistry.getContext());
             }
         };
     }