Fix testEnterVrInOverviewMode flakiness

Fixes VrShellTransitionTest#testEnterVrInOverviewMode being flaky due to
trying to call launchInVr with a null pointer for the launch intent.

Change-Id: Ic4b661fbf430e65a2a51923c2652a18acf11ac86
Reviewed-on: https://chromium-review.googlesource.com/912610Reviewed-by: Bill Orr <billorr@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#535920}

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/VrShellTransitionTest.java

@@ -308,6 +308,7 @@ public class VrShellTransitionTest {
         Assert.assertTrue(activity.isInOverviewMode());
 
         MockVrDaydreamApi mockApi = new MockVrDaydreamApi();
+        mockApi.setForwardSetupIntent(true);
         VrShellDelegateUtils.getDelegateInstance().overrideDaydreamApiForTesting(mockApi);
         Assert.assertTrue(VrTransitionUtils.forceEnterVr());
         VrTransitionUtils.waitForVrEntry(POLL_TIMEOUT_LONG_MS);

chrome/android/javatests/src/org/chromium/chrome/browser/vr_shell/mock/MockVrDaydreamApi.java

@@ -8,6 +8,8 @@ import android.app.PendingIntent;
 import android.content.ComponentName;
 import android.content.Intent;
 
+import com.google.vr.ndk.base.DaydreamApi;
+
 import org.chromium.chrome.browser.vr_shell.VrDaydreamApi;
 
 /**
@@ -17,6 +19,7 @@ public class MockVrDaydreamApi implements VrDaydreamApi {
     private boolean mLaunchInVrCalled;
     private boolean mExitFromVrCalled;
     private boolean mLaunchVrHomescreenCalled;
+    private boolean mForwardSetupIntent;
 
     @Override
     public boolean isDaydreamReadyDevice() {
@@ -88,6 +91,13 @@ public class MockVrDaydreamApi implements VrDaydreamApi {
 
     @Override
     public Intent setupVrIntent(Intent intent) {
+        if (mForwardSetupIntent) {
+            return DaydreamApi.setupVrIntent(intent);
+        }
         return null;
     }
+
+    public void setForwardSetupIntent(boolean forward) {
+        mForwardSetupIntent = forward;
+    }
 }