Clean up WebVR RequestPresent and make callback asynchronous.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
index bea4861e16ca4a7407a987c0709897a0757c474d..ed98793eb158000bb485305bc3d2d4ab7ca7c919 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellDelegate.java
@@ -11,6 +11,7 @@ import android.content.Intent;
 import android.content.pm.ActivityInfo;
 import android.os.StrictMode;
 import android.os.SystemClock;
+import android.support.annotation.IntDef;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewGroup.LayoutParams;
@@ -28,6 +29,8 @@ import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tab.TabObserver;
 import org.chromium.content_public.common.BrowserControlsState;
 
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationTargetException;
 
@@ -40,6 +43,13 @@ public class VrShellDelegate {
     // Pseudo-random number to avoid request id collisions.
     public static final int EXIT_VR_RESULT = 721251;
 
+    public static final int ENTER_VR_NOT_NECESSARY = 0;
+    public static final int ENTER_VR_CANCELLED = 1;
+    public static final int ENTER_VR_REQUESTED = 2;
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({ENTER_VR_NOT_NECESSARY, ENTER_VR_CANCELLED, ENTER_VR_REQUESTED})
+    public @interface EnterVRResult {}
+
     // TODO(bshe): These should be replaced by string provided by NDK. Currently, it only available
     // in SDK and we don't want add dependency to SDK just to get these strings.
     private static final String DAYDREAM_VR_EXTRA = "android.intent.extra.VR_LAUNCH";
@@ -48,16 +58,12 @@ public class VrShellDelegate {
 
     private static final String VR_ACTIVITY_ALIAS =
             "org.chromium.chrome.browser.VRChromeTabbedActivity";
-    private static final String DAYDREAM_DON_TYPE = "DAYDREAM_DON_TYPE";
-
-    private static final int DAYDREAM_DON_TYPE_VR_SHELL = 0;
-    private static final int DAYDREAM_DON_TYPE_WEBVR = 1;
-    private static final int DAYDREAM_DON_TYPE_AUTO = 2;
 
     private static final long REENTER_VR_TIMEOUT_MS = 1000;
 
     private final ChromeTabbedActivity mActivity;
     private final TabObserver mTabObserver;
+    private final Intent mEnterVRIntent;
 
     private boolean mVrAvailable;
     private Boolean mVrShellEnabled;
@@ -80,8 +86,13 @@ public class VrShellDelegate {
 
     public VrShellDelegate(ChromeTabbedActivity activity) {
         mActivity = activity;
-        mVrAvailable = maybeFindVrClasses() && isVrCoreCompatible();
-        createVrDaydreamApi();
+        mVrAvailable = maybeFindVrClasses() && isVrCoreCompatible() && createVrDaydreamApi();
+        if (mVrAvailable) {
+            mEnterVRIntent = mVrDaydreamApi.createVrIntent(
+                    new ComponentName(mActivity, VR_ACTIVITY_ALIAS));
+        } else {
+            mEnterVRIntent = null;
+        }
         mTabObserver = new EmptyTabObserver() {
             @Override
             public void onContentChanged(Tab tab) {
@@ -105,9 +116,8 @@ public class VrShellDelegate {
      * class can be initialized.
      */
     public void onNativeLibraryReady() {
-        if (mVrAvailable) {
-            mNativeVrShellDelegate = nativeInit();
-        }
+        if (!mVrAvailable) return;
+        mNativeVrShellDelegate = nativeInit();
     }
 
     @SuppressWarnings("unchecked")
@@ -135,28 +145,28 @@ public class VrShellDelegate {
     /**
      * Handle a VR intent, entering VR in the process.
      */
-    public boolean enterVRFromIntent(Intent intent) {
+    public void enterVRFromIntent(Intent intent) {
+        if (!mVrAvailable) return;
         assert isVrIntent(intent);
-        int transitionType = intent.getIntExtra(DAYDREAM_DON_TYPE, DAYDREAM_DON_TYPE_VR_SHELL);
-        if (!isVrShellEnabled()) {
-            assert transitionType != DAYDREAM_DON_TYPE_VR_SHELL;
+        if (enterVR()) {
+            if (mRequestedWebVR) {
+                nativeSetPresentResult(mNativeVrShellDelegate, true);
+                mVrShell.setWebVrModeEnabled(true);
+            }
+        } else {
+            if (mRequestedWebVR) nativeSetPresentResult(mNativeVrShellDelegate, false);
+            mVrDaydreamApi.exitFromVr(EXIT_VR_RESULT, new Intent());
         }
 
-        boolean inWebVR = transitionType == DAYDREAM_DON_TYPE_WEBVR
-                || (transitionType == DAYDREAM_DON_TYPE_AUTO
-                        && (!isVrShellEnabled() || mRequestedWebVR));
         mRequestedWebVR = false;
-        Tab tab = mActivity.getActivityTab();
-        if (!canEnterVR(inWebVR, tab)) return false;
+    }
 
-        // TODO(mthiesse): We should handle switching between webVR and VR Shell mode through
-        // intents.
+    private boolean enterVR() {
         if (mInVr) return true;
-
         mVrDaydreamApi.setVrModeEnabled(true);
 
-        mTab = tab;
-        mTab.addObserver(mTabObserver);
+        Tab tab = mActivity.getActivityTab();
+        if (!canEnterVR(tab)) return false;
 
         mRestoreOrientation = mActivity.getRequestedOrientation();
         mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
@@ -164,10 +174,12 @@ public class VrShellDelegate {
             mActivity.setRequestedOrientation(mRestoreOrientation);
             return false;
         }
+        mInVr = true;
+        mTab = tab;
+        mTab.addObserver(mTabObserver);
         addVrViews();
         setupVrModeWindowFlags();
         mVrShell.initializeNative(mTab, this);
-        if (inWebVR) mVrShell.setWebVrModeEnabled(true);
         mVrShell.setCloseButtonListener(new Runnable() {
             @Override
             public void run() {
@@ -177,18 +189,18 @@ public class VrShellDelegate {
         // onResume needs to be called on GvrLayout after initialization to make sure DON flow work
         // properly.
         mVrShell.resume();
-        mInVr = true;
         mTab.updateFullscreenEnabledState();
         return true;
     }
 
-    private boolean canEnterVR(boolean inWebVR, Tab tab) {
+    private boolean canEnterVR(Tab tab) {
         if (!LibraryLoader.isInitialized()) {
             return false;
         }
         // If vr isn't in the build, or we haven't initialized yet, or vr shell is not enabled and
         // this is not a web vr request, then return immediately.
-        if (!mVrAvailable || mNativeVrShellDelegate == 0 || (!isVrShellEnabled() && !inWebVR)) {
+        if (!mVrAvailable || mNativeVrShellDelegate == 0
+                || (!isVrShellEnabled() && !mRequestedWebVR)) {
             return false;
         }
         // TODO(mthiesse): When we have VR UI for opening new tabs, etc., allow VR Shell to be
@@ -204,28 +216,38 @@ public class VrShellDelegate {
         return true;
     }
 
-    /**
-     * Enters VR Shell, displaying browser UI and tab contents in VR.
-     *
-     * @param inWebVR If true should begin displaying WebVR content rather than the VrShell UI.
-     */
     @CalledByNative
-    public void enterVRIfNecessary(boolean inWebVR) {
-        if (mInVr) {
-            if (inWebVR) mVrShell.setWebVrModeEnabled(true);
-            return;
-        }
-        if (!canEnterVR(inWebVR, mActivity.getActivityTab())) return;
-
-        // TODO(mthiesse): There's a GVR bug where they're not calling us back with the intent we
-        // ask them to when we call DaydreamApi#launchInVr. As a temporary hack, remember locally
-        // that we want to enter webVR.
+    private void presentRequested(boolean inWebVR) {
+        // TODO(mthiesse): There's a GVR bug where they're not calling us back with the
+        // intent we ask them to when we call DaydreamApi#launchInVr. As a temporary hack,
+        // remember locally that we want to enter webVR.
         mRequestedWebVR = inWebVR;
-        Intent intent = createDaydreamIntent(
-                inWebVR ? DAYDREAM_DON_TYPE_WEBVR : DAYDREAM_DON_TYPE_VR_SHELL);
+        switch (enterVRIfNecessary()) {
+            case ENTER_VR_NOT_NECESSARY:
+                mVrShell.setWebVrModeEnabled(true);
+                nativeSetPresentResult(mNativeVrShellDelegate, true);
+                mRequestedWebVR = false;
+                break;
+            case ENTER_VR_CANCELLED:
+                nativeSetPresentResult(mNativeVrShellDelegate, false);
+                mRequestedWebVR = false;
+                break;
+            case ENTER_VR_REQUESTED:
+                break;
+        }
+    }
 
-        mVrDaydreamApi.launchInVr(
-                PendingIntent.getActivity(mActivity, 0, intent, PendingIntent.FLAG_ONE_SHOT));
+    /**
+     * Enters VR Shell if necessary, displaying browser UI and tab contents in VR.
+     */
+    @EnterVRResult
+    public int enterVRIfNecessary() {
+        if (!mVrAvailable) return ENTER_VR_CANCELLED;
+        if (mInVr) return ENTER_VR_NOT_NECESSARY;
+        if (!canEnterVR(mActivity.getActivityTab())) return ENTER_VR_CANCELLED;
+
+        mVrDaydreamApi.launchInVr(getPendingEnterVRIntent());
+        return ENTER_VR_REQUESTED;
     }
 
     @CalledByNative
@@ -243,9 +265,18 @@ public class VrShellDelegate {
      * Resumes VR Shell.
      */
     public void maybeResumeVR() {
+        if (!mVrAvailable) return;
+        // TODO(mthiesse): Register the intent when on a page that supports WebVR, even if VrShell
+        // isn't enabled.
         if (isVrShellEnabled()) {
             registerDaydreamIntent();
         }
+        // If this is still set, it means the user backed out of the DON flow, and we won't be
+        // receiving an intent from daydream.
+        if (mRequestedWebVR) {
+            nativeSetPresentResult(mNativeVrShellDelegate, false);
+            mRequestedWebVR = false;
+        }
 
         // TODO(bshe): Ideally, we do not need two gvr context exist at the same time. We can
         // probably shutdown non presenting gvr when presenting and create a new one after exit
@@ -272,7 +303,7 @@ public class VrShellDelegate {
                 StrictMode.setThreadPolicy(oldPolicy);
             }
         } else if (mLastVRExit + REENTER_VR_TIMEOUT_MS > SystemClock.uptimeMillis()) {
-            enterVRIfNecessary(mRequestedWebVR);
+            enterVRIfNecessary();
         }
     }
 
@@ -280,9 +311,8 @@ public class VrShellDelegate {
      * Pauses VR Shell.
      */
     public void maybePauseVR() {
-        if (isVrShellEnabled()) {
-            unregisterDaydreamIntent();
-        }
+        if (!mVrAvailable) return;
+        unregisterDaydreamIntent();
 
         if (mNonPresentingGvrContext != null) {
             mNonPresentingGvrContext.pause();
@@ -299,12 +329,14 @@ public class VrShellDelegate {
      * @return Whether or not we exited VR.
      */
     public boolean exitVRIfNecessary(boolean returnTo2D) {
+        if (!mVrAvailable) return false;
         if (!mInVr) return false;
         shutdownVR(returnTo2D);
         return true;
     }
 
     public void onExitVRResult(int resultCode) {
+        assert mVrAvailable;
         if (resultCode == Activity.RESULT_OK) {
             mVrDaydreamApi.setVrModeEnabled(false);
         } else {
@@ -313,33 +345,22 @@ public class VrShellDelegate {
         }
     }
 
-    private Intent createDaydreamIntent(int transitionType) {
-        if (mVrDaydreamApi == null) return null;
-        // TODO(bshe): Ideally, this should go through ChromeLauncherActivity. To avoid polluting
-        // metrics, use the VR Activity alias for now.
-        Intent intent = mVrDaydreamApi.createVrIntent(
-                new ComponentName(mActivity, VR_ACTIVITY_ALIAS));
-        intent.putExtra(DAYDREAM_DON_TYPE, transitionType);
-        return intent;
+    private PendingIntent getPendingEnterVRIntent() {
+        return PendingIntent.getActivity(mActivity, 0, mEnterVRIntent, PendingIntent.FLAG_ONE_SHOT);
     }
 
     /**
      * Registers the Intent to fire after phone inserted into a headset.
      */
     private void registerDaydreamIntent() {
-        if (mVrDaydreamApi == null) return;
-        Intent intent = createDaydreamIntent(DAYDREAM_DON_TYPE_AUTO);
-        mVrDaydreamApi.registerDaydreamIntent(
-                PendingIntent.getActivity(mActivity, 0, intent, PendingIntent.FLAG_ONE_SHOT));
+        mVrDaydreamApi.registerDaydreamIntent(getPendingEnterVRIntent());
     }
 
     /**
      * Unregisters the Intent which registered by this context if any.
      */
     private void unregisterDaydreamIntent() {
-        if (mVrDaydreamApi != null) {
-            mVrDaydreamApi.unregisterDaydreamIntent();
-        }
+        mVrDaydreamApi.unregisterDaydreamIntent();
     }
 
     @CalledByNative
@@ -371,6 +392,7 @@ public class VrShellDelegate {
      */
     private void shutdownVR(boolean returnTo2D) {
         if (!mInVr) return;
+        mRequestedWebVR = false;
         if (returnTo2D) {
             mVrDaydreamApi.exitFromVr(EXIT_VR_RESULT, new Intent());
         } else {
@@ -404,22 +426,20 @@ public class VrShellDelegate {
                     (VrCoreVersionChecker) mVrCoreVersionCheckerConstructor.newInstance();
         } catch (InstantiationException | IllegalAccessException | IllegalArgumentException
                 | InvocationTargetException | NoSuchMethodException e) {
-            Log.e(TAG, "Unable to instantiate VrCoreVersionChecker", e);
+            Log.d(TAG, "Unable to instantiate VrCoreVersionChecker", e);
             return false;
         }
         return mVrCoreVersionChecker.isVrCoreCompatible();
     }
 
     private boolean createVrDaydreamApi() {
-        if (!mVrAvailable) return false;
-
         try {
             Constructor<?> vrPrivateApiConstructor =
                     mVrDaydreamApiClass.getConstructor(Activity.class);
             mVrDaydreamApi = (VrDaydreamApi) vrPrivateApiConstructor.newInstance(mActivity);
         } catch (InstantiationException | IllegalAccessException | IllegalArgumentException
-                | InvocationTargetException | NoSuchMethodException e) {
-            Log.e(TAG, "Unable to instantiate VrDaydreamApi", e);
+                | InvocationTargetException | NoSuchMethodException | SecurityException e) {
+            Log.d(TAG, "Unable to instantiate VrDaydreamApi", e);
             return false;
         }
         return true;
@@ -521,13 +541,6 @@ public class VrShellDelegate {
     }
 
     /**
-     * @return Whether or not VR Shell is currently enabled.
-     */
-    public boolean isVrInitialized() {
-        return mVrDaydreamApi != null;
-    }
-
-    /**
      * @return Pointer to the native VrShellDelegate object.
      */
     @CalledByNative
@@ -536,4 +549,5 @@ public class VrShellDelegate {
     }
 
     private native long nativeInit();
+    private native void nativeSetPresentResult(long nativeVrShellDelegate, boolean result);
 }