Clean up VR Shell mode transitions (and fix potential webvr startup race).

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

Index: chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
index fae9c8cca1c4a2fc7f95f68b7d5a5c00d60fdd8f..a3d53cd2f9599a776e0b892b4241eb9181af589f 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/vr_shell/VrShellImpl.java
@@ -114,7 +114,7 @@ public class VrShellImpl extends GvrLayout implements GLSurfaceView.Renderer, Vr
     }
 
     @Override
-    public void initializeNative(Tab currentTab, VrShellDelegate delegate) {
+    public void initializeNative(Tab currentTab, VrShellDelegate delegate, boolean forWebVR) {
         assert currentTab.getContentViewCore() != null;
         mTab = currentTab;
         mContentCVC = mTab.getContentViewCore();
@@ -128,8 +128,8 @@ public class VrShellImpl extends GvrLayout implements GLSurfaceView.Renderer, Vr
                 uiContentView, mUiContents, mUiVrWindowAndroid);
 
         mNativeVrShell = nativeInit(mContentCVC.getWebContents(),
-                mContentVrWindowAndroid.getNativePointer(),
-                mUiContents, mUiVrWindowAndroid.getNativePointer());
+                mContentVrWindowAndroid.getNativePointer(), mUiContents,
+                mUiVrWindowAndroid.getNativePointer(), forWebVR);
         mGlSurfaceView.setOnTouchListener(new View.OnTouchListener() {
             @Override
             @SuppressLint("ClickableViewAccessibility")
@@ -367,7 +367,7 @@ public class VrShellImpl extends GvrLayout implements GLSurfaceView.Renderer, Vr
     }
 
     private native long nativeInit(WebContents contentWebContents, long nativeContentWindowAndroid,
-            WebContents uiWebContents, long nativeUiWindowAndroid);
+            WebContents uiWebContents, long nativeUiWindowAndroid, boolean forWebVR);
     private native void nativeSetDelegate(long nativeVrShell, VrShellDelegate delegate);
     private native void nativeGvrInit(long nativeVrShell, long nativeGvrApi);
     private native void nativeDestroy(long nativeVrShell);