Revert "VR: Use isInVrSession API to keep Chrome in VR until user has left VR"

This reverts commit dc55fd14.

Reason for revert: Suspected to have broken chrome_public_test_vr_apk on main waterfall
https://ci.chromium.org/buildbot/chromium.android/Marshmallow%20Phone%20Tester%20%28rel%29/?limit=200
first failing build contains this cl:
https://ci.chromium.org/buildbot/chromium.android/Marshmallow%20Phone%20Tester%20%28rel%29/3088

Original change's description:
> VR: Use isInVrSession API to keep Chrome in VR until user has left VR
> 
> This fixes the Daydream Dashboard issues so that if Chrome is simply
> stopped/started in VR without any intents, Chrome stays in VR.
> 
> Also makes resuming Chrome from DD home way faster if Chrome was
> already in VR.
> 
> Bug: 780887
> Change-Id: Iab7f713bfc5b85972f908ea141e3b495297d7286
> Reviewed-on: https://chromium-review.googlesource.com/944547
> Reviewed-by: Yash Malik <ymalik@chromium.org>
> Commit-Queue: Michael Thiessen <mthiesse@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#540403}

TBR=mthiesse@chromium.org,ymalik@chromium.org

Change-Id: I7ae67f5d23d816796cc7f567792e181900b3012a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 780887
Reviewed-on: https://chromium-review.googlesource.com/946709Reviewed-by: Benjamin Pastene <bpastene@chromium.org>
Commit-Queue: Benjamin Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540588}

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

@@ -77,12 +77,6 @@ public interface VrDaydreamApi {
      */
     Intent setupVrIntent(Intent intent);
 
-    /**
-     * Whether the user is currently in a VR session. Note that this should be treated as heuristic,
-     * and may at times be wrong.
-     */
-    boolean isInVrSession();
-
     /**
      * Closes this DaydreamApi instance.
      */

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

@@ -134,11 +134,6 @@ public class VrDaydreamApiImpl implements VrDaydreamApi {
         return DaydreamApi.setupVrIntent(intent);
     }
 
-    @Override
-    public boolean isInVrSession() {
-        return DaydreamApi.isInVrSession(mContext);
-    }
-
     @Override
     public void close() {
         if (mDaydreamApi == null) return;

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

@@ -971,16 +971,16 @@ public class VrShellDelegate
     }
 
     private void onVrIntent() {
-        mNeedsAnimationCancel = true;
-        mInVrAtChromeLaunch = true;
         if (mInVr) return;
 
+        mNeedsAnimationCancel = true;
         mEnterVrOnStartup = true;
 
         // TODO(mthiesse): Assuming we've gone through DON flow saves ~2 seconds on VR entry. See
         // the comments in enterVr(). This may not always be the case in the future, but for now
         // it's a reasonable assumption.
         mDonSucceeded = true;
+        mInVrAtChromeLaunch = true;
 
         if (!mPaused) enterVrAfterDon();
     }
@@ -1362,23 +1362,24 @@ public class VrShellDelegate
             });
         }
 
-        mCancellingEntryAnimation = false;
-
         if (mEnterVrOnStartup) {
             // This means that Chrome was started with a VR intent, so we should enter VR.
             // TODO(crbug.com/776235): VR intents are dispatched to ChromeActivity via a launcher
             // which should handle the DON flow to simplify the logic in VrShellDelegate.
             assert !mProbablyInDon;
             if (DEBUG_LOGS) Log.i(TAG, "onResume: entering VR mode for VR intent");
+            mCancellingEntryAnimation = false;
             if (enterVrInternal() == ENTER_VR_CANCELLED) {
                 cancelPendingVrEntry();
             }
         } else if (mDonSucceeded) {
+            mCancellingEntryAnimation = false;
             handleDonFlowSuccess();
         } else {
             if (mProbablyInDon) {
                 // This means the user backed out of the DON flow, and we won't be entering VR.
                 maybeSetPresentResult(false, mDonSucceeded);
+
                 shutdownVr(true, false);
             }
             // If we were resumed at the wrong density, we need to trigger activity recreation.
@@ -1425,6 +1426,10 @@ public class VrShellDelegate
         // are safe.
         if (mInVr) mVrShell.pause();
         if (mShowingDaydreamDoff || mProbablyInDon) return;
+
+        // TODO(mthiesse): When the user resumes Chrome in a 2D context, we don't want to tear down
+        // VR UI, so for now, exit VR.
+        shutdownVr(true /* disableVrMode */, false /* stayingInChrome */);
     }
 
     protected void onPause() {
@@ -1435,6 +1440,10 @@ public class VrShellDelegate
         unregisterDaydreamIntent(mVrDaydreamApi);
         if (mVrSupportLevel == VrSupportLevel.VR_NOT_AVAILABLE) return;
 
+        // TODO(ymalik): We should be able to remove this if we handle it for multi-window in
+        // {@link onMultiWindowModeChanged} since we're calling it in onStop.
+        if (!mInVr && !mProbablyInDon) cancelPendingVrEntry();
+
         // When the active web page has a vrdisplayactivate event handler,
         // mListeningForWebVrActivate should be set to true, which means a vrdisplayactive event
         // should be fired once DON flow finished. However, DON flow will pause our activity,
@@ -1453,12 +1462,12 @@ public class VrShellDelegate
     private void onStart() {
         mStopped = false;
         if (mDonSucceeded) setWindowModeForVr();
-        if (mInVr && !mVrDaydreamApi.isInVrSession()) shutdownVr(true, false);
     }
 
     private void onStop() {
         if (DEBUG_LOGS) Log.i(TAG, "onStop");
         mStopped = true;
+        if (!mProbablyInDon) cancelPendingVrEntry();
         assert !mCancellingEntryAnimation;
     }
 

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

@@ -100,9 +100,4 @@ public class MockVrDaydreamApi implements VrDaydreamApi {
     public void setForwardSetupIntent(boolean forward) {
         mForwardSetupIntent = forward;
     }
-
-    @Override
-    public boolean isInVrSession() {
-        return true;
-    }
 }