Switch WebVR to handle GvrApi management through VrShellDelegate

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 46a55a1fa806a86f66f032cb89be127d95396dac..6e4f2f79c18d32f9596ab2b809cb0f5261717f46 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
@@ -14,6 +14,8 @@ import android.view.ViewGroup.LayoutParams;
 import android.view.WindowManager;
 
 import org.chromium.base.Log;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
 import org.chromium.chrome.browser.ChromeTabbedActivity;
 
 import java.lang.reflect.Constructor;
@@ -22,6 +24,7 @@ import java.lang.reflect.InvocationTargetException;
 /**
  * Manages interactions with the VR Shell.
  */
+@JNINamespace("vr_shell")
 public class VrShellDelegate {
     private static final String TAG = "VrShellDelegate";
 
@@ -35,6 +38,7 @@ public class VrShellDelegate {
     private int mRestoreSystemUiVisibilityFlag = -1;
     private ViewGroup mParentView;
     private String mVrExtra;
+    private long mNativeVrShellDelegate;
 
     public VrShellDelegate(ChromeTabbedActivity activity, ViewGroup parentView) {
         mActivity = activity;
@@ -52,6 +56,10 @@ public class VrShellDelegate {
         }
     }
 
+    public void onNativeLibraryReady() {

[Ted C, 2016/09/20 20:31:11]

all public methods should have some sort of documentation

+        mNativeVrShellDelegate = nativeInit();
+    }
+
     @SuppressWarnings("unchecked")
     private Class<? extends VrShellInterface> maybeFindVrShell() {
         try {
@@ -70,7 +78,7 @@ public class VrShellDelegate {
      * @Returns Whether or not we are in VR when this function returns.
      */
     public boolean enterVRIfNecessary() {

[Ted C, 2016/09/20 20:31:11]

could this just take a boolean param isWebVR?  same for exit?

-        if (!mVrShellEnabled) return false;
+        if (!mVrShellEnabled || mNativeVrShellDelegate == 0) return false;
         if (mInVr) return true;
         // VrShell must be initialized in Landscape mode due to a bug in the GVR library.
         mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
@@ -80,12 +88,31 @@ public class VrShellDelegate {
         }
         addVrViews();
         setupVrModeWindowFlags();
-        mVrShellView.onNativeLibraryReady();
+        mVrShellView.onNativeLibraryReady(mNativeVrShellDelegate);
         mVrShellView.setVrModeEnabled(true);
         mInVr = true;
         return true;
     }
 
+    @CalledByNative
+    public boolean enterWebVRIfNecessary() {
+        if (enterVRIfNecessary()) {
+            mVrShellView.setWebVrModeEnabled(true);
+            return true;
+        }
+        return false;
+    }
+
+    @CalledByNative
+    public boolean exitWebVRIfNecessary() {
+        if (!mInVr) return false;
+        mVrShellView.setWebVrModeEnabled(false);
+        // TODO(bajones): Once VR Shell can be invoked outside of WebVR this
+        // should no longer exit the shell outright. Need a way to determine
+        // how VrShell was created.
+        return exitVRIfNecessary();
+    }
+
     /**
      * Resumes VR Shell.
      */
@@ -107,6 +134,12 @@ public class VrShellDelegate {
      */
     public boolean exitVRIfNecessary() {
         if (!mInVr) return false;
+        if (nativeExitVRIfNecessary(mNativeVrShellDelegate)) {
+            // In this scenario we need to wait for WebVR to shut down before
+            // removing the VrShell. exitVRIfNecessary will be called again (by
+            // exitWebVRIfNecessary) when it's safe to destroy the VrShell.

[Ted C, 2016/09/20 20:31:11]

that is an odd semantics.  should we pull out a distinct destroy call and have
it call that instead of a method meaning two things?

+            return true;
+        }
         mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
         mVrShellView.setVrModeEnabled(false);
         mVrShellView.pause();
@@ -195,4 +228,8 @@ public class VrShellDelegate {
     public boolean isVrShellEnabled() {
         return mVrShellEnabled;
     }
+
+    private native long nativeInit();
+
+    private native boolean nativeExitVRIfNecessary(long nativeVrShellDelegate);
 }