VR: Fix Headset insertion on N devices.

https://chromium-review.googlesource.com/c/chromium/src/+/1007922
failed to account for the animation cancel logic properly.

Bug: 831589
Change-Id: I46081899198e1381310c758bc9e6f937ddf1cd2f
Reviewed-on: https://chromium-review.googlesource.com/1010524Reviewed-by: Yash Malik <ymalik@chromium.org>
Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550249}

chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java

@@ -1900,6 +1900,7 @@ public class VrShellDelegate
         mListeningForWebVrActivate = listening;
         if (mListeningForWebVrActivate) {
             registerDaydreamIntent(mActivity);
+            if (mNeedsAnimationCancel || mCancellingEntryAnimation) return;
             if (mAutopresentWebVr || mActivateFromHeadsetInsertion) {
                 // Dispatch vrdisplayactivate so that the WebVr page can call requestPresent
                 // to start presentation.

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

@@ -4,8 +4,6 @@
 
 package org.chromium.chrome.browser.vr_shell;
 
-import org.junit.Assert;
-
 import org.chromium.base.ThreadUtils;
 import org.chromium.chrome.browser.ChromeActivity;
 
@@ -16,7 +14,6 @@ import org.chromium.chrome.browser.ChromeActivity;
  * - Allows us to have test-specific behavior if necessary without changing production code
  */
 public class TestVrShellDelegate extends VrShellDelegate {
-    private boolean mOnResumeCalled;
     private Runnable mOnVSyncPausedCallback;
     private static TestVrShellDelegate sInstance;
     private boolean mDisableVrBrowsing;
@@ -110,7 +107,6 @@ public class TestVrShellDelegate extends VrShellDelegate {
             mTestWorkaroundDontCancelVrEntryOnResume = true;
         }
         super.onResume();
-        mOnResumeCalled = true;
         mTestWorkaroundDontCancelVrEntryOnResume = false;
     }
 
@@ -132,19 +128,6 @@ public class TestVrShellDelegate extends VrShellDelegate {
         return mExpectingBroadcast;
     }
 
-    /**
-     * Make sure that onResume is called before onPause.
-     *
-     * This is necessary since we don't want weird problems to show up caused by the delayed
-     * onResume being called after onPause.
-     */
-    @Override
-    protected void onPause() {
-        Assert.assertTrue(mOnResumeCalled);
-        mOnResumeCalled = false;
-        super.onPause();
-    }
-
     /**
      * If we need to know when the normal VSync gets paused, we have a small window between when
      * the VrShell is created and we actually enter VR to set the callback. So, do it immediately