Add sign-in and token retrieval to Blimp

blimp/client/android/javatests/src/org/chromium/blimp/auth/MockTokenSource.java

Index: blimp/client/android/javatests/src/org/chromium/blimp/auth/MockTokenSource.java
diff --git a/blimp/client/android/javatests/src/org/chromium/blimp/auth/MockTokenSource.java b/blimp/client/android/javatests/src/org/chromium/blimp/auth/MockTokenSource.java
new file mode 100644
index 0000000000000000000000000000000000000000..2b4132fdce09554099d72b1b80adc4d43abe1e40
--- /dev/null
+++ b/blimp/client/android/javatests/src/org/chromium/blimp/auth/MockTokenSource.java
@@ -0,0 +1,97 @@
+// Copyright 2015 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.auth;
+
+import android.content.Intent;
+import android.os.Handler;
+import android.os.Message;
+
+import com.google.android.gms.common.ConnectionResult;
+
+import junit.framework.Assert;
+
+/**
+ * Test implementation of a TokenSource.  Has the following features:
+ * - Can return a specific token.
+ * - Can mimic a specific number of transient failures before a success or unrecoverable failure.
+ * - Can mimic an unrecoverable failure.
+ */
+public class MockTokenSource extends Handler implements TokenSource {
+    private static final int MSG_QUERY_TOKEN = 1;
+
+    private TokenSource.Callback mCallback;

[nyquist, 2015/09/29 23:38:40]

Nit: Could you put final members before non-final members?

[David Trainor- moved to gerrit, 2015/10/05 15:19:07]

Done.

+
+    private final String mCorrectToken;
+
+    /** Whether or not to fail in a non-transient way after all transient failures. */
+    private final boolean mFailHard;
+
+    /**
+     * The number of transient failures left to simulate before a successful or non-transient
+     * failure is reported.
+     */
+    private int mTransientFailuresLeft;
+
+    /** Whether or not a non-transient failure has already been reported. */
+    private boolean mAlreadyFailedHard;
+
+    /**
+     * @param correctToken          The token to return on success.
+     * @param transientFailureCount The number of transient failures to emit.
+     * @param failsHardAfter        Whether or not to show a non-transient failure or successfully
+     *                              return the token after all transient failures.
+     */
+    public MockTokenSource(String correctToken, int transientFailureCount, boolean failsHardAfter) {
+        mCorrectToken = correctToken;
+        mTransientFailuresLeft = transientFailureCount;
+        mFailHard = failsHardAfter;
+    }
+
+    // TokenSource implementation.
+    @Override
+    public void destroy() {}
+
+    @Override
+    public void setCallback(TokenSource.Callback callback) {
+        mCallback = callback;
+    }
+
+    @Override
+    public void getToken() {
+        Assert.assertFalse("getToken() called after already returning a successful token.",
+                isRetrievingToken());
+        Assert.assertFalse("getToken() called after failing in an unrecoverable way.",
+                mAlreadyFailedHard);
+        sendEmptyMessage(MSG_QUERY_TOKEN);
+    }
+
+    @Override
+    public boolean isRetrievingToken() {
+        return hasMessages(MSG_QUERY_TOKEN);
+    }
+
+    @Override
+    public int tokenIsInvalid(String token) {
+        return ConnectionResult.SUCCESS;
+    }
+
+    @Override
+    public void onAccountSelected(Intent data) {}
+
+    // Handler overrides.
+    @Override
+    public final void handleMessage(Message msg) {
+        if (msg.what != MSG_QUERY_TOKEN) return;
+        if (mTransientFailuresLeft > 0) {
+            mCallback.onTokenUnavailable(true);
+        } else if (mFailHard) {
+            mAlreadyFailedHard = true;
+            mCallback.onTokenUnavailable(false);
+        } else {
+            mCallback.onTokenReceived(mCorrectToken);
+        }
+        --mTransientFailuresLeft;
+    }
+}