Repository: azuread/microsoft-authentication-library-common-for-android
Issue: Null pointer on AcquireTokenResult.getSucceeded 

COBO app reported a null pointer on a failed silent flow where`AcquireTokenResult` is null. 

StackTrace
```
com.microsoft.intune.common.presentationcomponent.abstraction.UiModelErrorState$Authentication@6b4a87a
2020-01-08T00:02:51.4700000	INFO	com.microsoft.intune.authentication.authcomponent.abstraction.AadTokenRepo	 9274	00002	Calling AAD auth library for Intune(ignored=true) token.
2020-01-08T00:02:51.6980000	WARNING	com.microsoft.intune.authentication.authcomponent.implementation.MsalAuthWrapper	 9274	00002	Silent MSAL auth failed.
	com.microsoft.identity.client.exception.MsalClientException: Attempt to invoke virtual method 'java.lang.Boolean com.microsoft.identity.common.internal.result.AcquireTokenResult.getSucceeded()' on a null object reference
		com.microsoft.identity.client.internal.controllers.MsalExceptionAdapter.msalExceptionFromBaseException(MsalExceptionAdapter.java:51)
		com.microsoft.identity.client.PublicClientApplication$9.onError(PublicClientApplication.java:1668)
		com.microsoft.identity.client.PublicClientApplication$9.onError(PublicClientApplication.java:1658)
		com.microsoft.identity.common.internal.controllers.CommandDispatcher$2.run(CommandDispatcher.java:176)
		android.os.Handler.handleCallback(Handler.java:883)
		android.os.Handler.dispatchMessage(Handler.java:100)
		android.os.Looper.loop(Looper.java:214)
		android.app.ActivityThread.main(ActivityThread.java:7356)
		java.lang.reflect.Method.invoke(Native Method)
		com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
		com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
	com.microsoft.identity.common.exception.ClientException: Attempt to invoke virtual method 'java.lang.Boolean com.microsoft.identity.common.internal.result.AcquireTokenResult.getSucceeded()' on a null object reference
		com.microsoft.identity.common.internal.controllers.ExceptionAdapter.baseExceptionFromException(ExceptionAdapter.java:252)
		com.microsoft.identity.common.internal.controllers.CommandDispatcher.executeCommand(CommandDispatcher.java:142)
		com.microsoft.identity.common.internal.controllers.CommandDispatcher.access$200(CommandDispatcher.java:52)
		com.microsoft.identity.common.internal.controllers.CommandDispatcher$1.run(CommandDispatcher.java:94)
		java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
		java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
		java.lang.Thread.run(Thread.java:919)
	java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Boolean com.microsoft.identity.common.internal.result.AcquireTokenResult.getSucceeded()' on a null object reference
		com.microsoft.identity.common.internal.controllers.TokenCommand.execute(TokenCommand.java:77)
		com.microsoft.identity.common.internal.controllers.TokenCommand.execute(TokenCommand.java:42)
		com.microsoft.identity.common.internal.controllers.CommandDispatcher.executeCommand(CommandDispatcher.java:137)
		com.microsoft.identity.common.internal.controllers.CommandDispatcher.access$200(CommandDispatcher.java:52)
		com.microsoft.identity.common.internal.controllers.CommandDispatcher$1.run(CommandDispatcher.java:94)
		java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
		java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
		java.lang.Thread.run(Thread.java:919)

```

Changed files:
common/src/main/java/com/microsoft/identity/common/internal/controllers/TokenCommand.java

diff --git a/common/src/main/java/com/microsoft/identity/common/internal/controllers/TokenCommand.java b/common/src/main/java/com/microsoft/identity/common/internal/controllers/TokenCommand.java
index 3f5b6e0cd..7748ade89 100644
--- a/common/src/main/java/com/microsoft/identity/common/internal/controllers/TokenCommand.java
+++ b/common/src/main/java/com/microsoft/identity/common/internal/controllers/TokenCommand.java
@@ -24,10 +24,7 @@ package com.microsoft.identity.common.internal.controllers;
 
 import android.content.Intent;
 
-import androidx.annotation.NonNull;
-
 import com.microsoft.identity.common.adal.internal.AuthenticationConstants;
-import com.microsoft.identity.common.exception.BaseException;
 import com.microsoft.identity.common.exception.ClientException;
 import com.microsoft.identity.common.exception.ErrorStrings;
 import com.microsoft.identity.common.exception.UiRequiredException;
@@ -35,9 +32,9 @@ import com.microsoft.identity.common.internal.request.AcquireTokenSilentOperatio
 import com.microsoft.identity.common.internal.request.OperationParameters;
 import com.microsoft.identity.common.internal.result.AcquireTokenResult;
 
-import java.io.IOException;
 import java.util.List;
-import java.util.concurrent.ExecutionException;
+
+import androidx.annotation.NonNull;
 
 public class TokenCommand extends BaseCommand<AcquireTokenResult> implements TokenOperation {
 
@@ -74,7 +71,7 @@ public class TokenCommand extends BaseCommand<AcquireTokenResult> implements Tok
                         (AcquireTokenSilentOperationParameters) getParameters()
                 );
 
-                if (result.getSucceeded()) {
+                if (result != null && result.getSucceeded()) {
                     com.microsoft.identity.common.internal.logging.Logger.verbose(
                             TAG + methodName,
                             "Executing with controller: "