Make ViewRoot the top of the ViewAndroid tree

chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
index ff97c0d5a2e30d0e3360285fbf0184c364026ead..93a35ab95b81069eee83ac2d01809799c25a1d9a 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeActivity.java
@@ -145,6 +145,7 @@ import org.chromium.printing.PrintingControllerImpl;
 import org.chromium.ui.base.ActivityWindowAndroid;
 import org.chromium.ui.base.DeviceFormFactor;
 import org.chromium.ui.base.PageTransition;
+import org.chromium.ui.base.ViewRoot;
 import org.chromium.ui.base.WindowAndroid;
 
 import java.util.ArrayList;
@@ -225,6 +226,7 @@ public abstract class ChromeActivity extends AsyncInitializationActivity
     private ProfileSyncService.SyncStateChangedListener mSyncStateChangedListener;
 
     private ActivityWindowAndroid mWindowAndroid;
+    private ViewRoot mViewRoot;
 
     private ChromeFullscreenManager mFullscreenManager;
     private boolean mCreatedFullscreenManager;
@@ -281,6 +283,7 @@ public abstract class ChromeActivity extends AsyncInitializationActivity
         getWindow().setBackgroundDrawable(getBackgroundDrawable());
         mWindowAndroid = new ChromeWindow(this);
         mWindowAndroid.restoreInstanceState(getSavedInstanceState());
+        mViewRoot = ViewRoot.create(mWindowAndroid);
 
         mFullscreenManager = createFullscreenManager();
         mCreatedFullscreenManager = true;
@@ -669,7 +672,7 @@ public abstract class ChromeActivity extends AsyncInitializationActivity
 
         setTabContentManager(new TabContentManager(this, getContentOffsetProvider(),
                 DeviceClassManager.enableSnapshots()));
-        mCompositorViewHolder.onNativeLibraryReady(mWindowAndroid, getTabContentManager());
+        mCompositorViewHolder.onNativeLibraryReady(mViewRoot, getTabContentManager());
 
         if (isContextualSearchAllowed() && ContextualSearchFieldTrial.isEnabled()) {
             mContextualSearchManager = new ContextualSearchManager(this, mWindowAndroid, this);
@@ -1002,6 +1005,11 @@ public abstract class ChromeActivity extends AsyncInitializationActivity
             if (selector != null) selector.destroy();
         }
 
+        if (mViewRoot != null) {
+            mViewRoot.destroy();
+            mViewRoot = null;
+        }
+
         if (mWindowAndroid != null) {
             mWindowAndroid.destroy();
             mWindowAndroid = null;
@@ -1426,6 +1434,13 @@ public abstract class ChromeActivity extends AsyncInitializationActivity
     }
 
     /**
+     * @return A {@link ViewRoot} instance.
+     */
+    public ViewRoot getViewRoot() {
+        return mViewRoot;
+    }
+
+    /**
      * @return A {@link WindowAndroid} instance.
      */
     public WindowAndroid getWindowAndroid() {