Introduce ViewRoot forwarding input/view events to native

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 e479484bc0a87756a3ab30a730e332fc0fce5651..b4819b4580f906e30cb8527c514fe1b4b6b11315 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
@@ -76,6 +76,7 @@ public class VrShellImpl extends GvrLayout implements VrShell {
     private WebContents mUiContents;
     private ContentViewCore mUiCVC;
     private VrWindowAndroid mUiVrWindowAndroid;
+    private ViewRoot mUiViewRoot;
 
     public VrShellImpl(Activity activity) {
         super(activity);
@@ -110,6 +111,9 @@ public class VrShellImpl extends GvrLayout implements VrShell {
 
         mUiVrWindowAndroid = new VrWindowAndroid(mActivity, mUiVirtualDisplay);
         mUiContents = WebContentsFactory.createWebContents(true, false);
+        mUiViewRoot = ViewRoot.create(mUiVrWindowAndroid);
+        mUiContents.initViewRoot(mUiViewRoot);
+
         mUiCVC = new ContentViewCore(mActivity, ChromeVersionInfo.getProductVersion());
         ContentView uiContentView = ContentView.createContentView(mActivity, mUiCVC);
         mUiCVC.initialize(ViewAndroidDelegate.createBasicDelegate(uiContentView),
@@ -171,7 +175,7 @@ public class VrShellImpl extends GvrLayout implements VrShell {
         Point size = new Point(surfaceWidth, surfaceHeight);
         mUiVirtualDisplay.update(size, size, dpr, null, null, null);
         mUiCVC.onSizeChanged(surfaceWidth, surfaceHeight, 0, 0);
-        getViewRoot(mUiCVC).onPhysicalBackingSizeChanged(surfaceWidth, surfaceHeight);
+        mUiViewRoot.onPhysicalBackingSizeChanged(surfaceWidth, surfaceHeight);
         nativeUIBoundsChanged(mNativeVrShell, surfaceWidth, surfaceHeight, dpr);
     }
 
@@ -184,14 +188,10 @@ public class VrShellImpl extends GvrLayout implements VrShell {
         Point size = new Point(surfaceWidth, surfaceHeight);
         mContentVirtualDisplay.update(size, size, dpr, null, null, null);
         mContentCVC.onSizeChanged(surfaceWidth, surfaceHeight, 0, 0);
-        getViewRoot(mContentCVC).onPhysicalBackingSizeChanged(surfaceWidth, surfaceHeight);
+        mTab.getViewRoot().onPhysicalBackingSizeChanged(surfaceWidth, surfaceHeight);
         nativeContentBoundsChanged(mNativeVrShell, surfaceWidth, surfaceHeight, dpr);
     }
 
-    private ViewRoot getViewRoot(ContentViewCore cvc) {
-        return cvc.getWindowAndroid().getViewRoot();
-    }
-
     @Override
     public boolean dispatchTouchEvent(MotionEvent event) {
         // Normally, touch event is dispatched to presentation view only if the phone is paired with