Introduce ViewRoot forwarding input/view events to native

content/public/android/java/src/org/chromium/content_public/browser/WebContents.java

Index: content/public/android/java/src/org/chromium/content_public/browser/WebContents.java
diff --git a/content/public/android/java/src/org/chromium/content_public/browser/WebContents.java b/content/public/android/java/src/org/chromium/content_public/browser/WebContents.java
index f263f059d1be0f7349ca2691178ebdb4c3f4797e..3ca2cc602288a7861a81c3d9710c7420832c80b4 100644
--- a/content/public/android/java/src/org/chromium/content_public/browser/WebContents.java
+++ b/content/public/android/java/src/org/chromium/content_public/browser/WebContents.java
@@ -10,6 +10,7 @@ import android.os.Parcelable;
 
 import org.chromium.base.VisibleForTesting;
 import org.chromium.ui.OverscrollRefreshHandler;
+import org.chromium.ui.base.ViewRoot;
 
 /**
  * The WebContents Java wrapper to allow communicating with the native WebContents object.
@@ -334,6 +335,12 @@ public interface WebContents extends Parcelable {
     public void reloadLoFiImages();
 
     /**
+     * Initializes the view hierarchy with {@link ViewRoot} set to the top of the tree.
+     * @param viewRoot The root of the view used to forward input/view events.
+     */
+    public void initViewRoot(ViewRoot viewRoot);

[boliu, 2017/01/03 19:16:11]

I think ViewRoot should be set and stored where WindowAndroid is set and stored,
eg add new param to CVC.initialize/updateWindowAndroid. This probably applies to
the content embedder as well. No need to invent new lifetime rules for ViewRoot

[Jinsuk Kim, 2017/01/04 10:45:02]

Done. It's just that I'm the one who put the comment in CVC telling people not
to add new stuff there... didn't want to do exactly that...

[boliu, 2017/01/04 17:45:10]

That's true.. you can move WindowAndroid out of CVC first

[Jinsuk Kim, 2017/01/05 11:03:12]

I like your suggestion s/WindowAndroid/ViewRoot passed into CVC.

+
+    /**
      * Sends a request to download the given image {@link url}.
      * This method delegates the call to the downloadImage() method of native WebContents.
      * @param url The URL of the image to download.