Blimp OAuth2 token retreival on application start up.

blimp/client/core/android/java/src/org/chromium/blimp/core/common/PreferencesUtil.java

Index: blimp/client/core/android/java/src/org/chromium/blimp/core/common/PreferencesUtil.java
diff --git a/blimp/client/core/android/java/src/org/chromium/blimp/core/common/PreferencesUtil.java b/blimp/client/core/android/java/src/org/chromium/blimp/core/common/PreferencesUtil.java
new file mode 100644
index 0000000000000000000000000000000000000000..582eb3514f01d240f8bae2e512e2318b8177f552
--- /dev/null
+++ b/blimp/client/core/android/java/src/org/chromium/blimp/core/common/PreferencesUtil.java
@@ -0,0 +1,51 @@
+// Copyright 2016 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.blimp.core.common;
+
+import org.chromium.base.ContextUtils;
+
+/**
+ * Blimp preferences utilities.
+ */
+public class PreferencesUtil {
+
+    /**
+     * Blimp switch preference key, also the key for this PreferenceFragment.
+     */
+    public static final String PREF_BLIMP_SWITCH = "blimp_switch";
+
+    /**
+     * Blimp assigner URL preference key.
+     */
+    public static final String PREF_ASSIGNER_URL = "blimp_assigner_url";
+
+    private static final String DEFAULT_ASSIGNER_URL =
+            "https://dev-blimp-pa.sandbox.googleapis.com/v1/assignment";
+
+    /**
+     * Reads the last used assigner from shared preference.
+     * @return The saved value of assigner preference, or the default development assigner URL
+     * if we didn't find the shared preference.
+     */
+    public static String getLastUsedAssigner() {
+        return ContextUtils.getAppSharedPreferences().getString(
+                PREF_ASSIGNER_URL, DEFAULT_ASSIGNER_URL);
+    }
+
+    /**
+     * @return Value of Blimp switch preference.
+     */
+    public static boolean isBlimpEnabled() {
+        return ContextUtils.getAppSharedPreferences().getBoolean(PREF_BLIMP_SWITCH, false);
+    }
+
+    /**
+     * Set the value of Blimp switch preference.
+     */
+    public static void setBlimpEnabled(boolean enabled) {
+        ContextUtils.getAppSharedPreferences().edit().putBoolean(PREF_BLIMP_SWITCH, enabled)
+            .apply();
+    }
+}