Introduce ViewRoot forwarding input/view events to native

ui/android/java/src/org/chromium/ui/base/ViewRoot.java

Index: ui/android/java/src/org/chromium/ui/base/ViewRoot.java
diff --git a/ui/android/java/src/org/chromium/ui/base/ViewRoot.java b/ui/android/java/src/org/chromium/ui/base/ViewRoot.java
index c224e8e3ed8c9cdfd31b3ed2e783e090ea42a4e7..23d7a3f35483f6f5fc89272b832a2822fe1fb5db 100644
--- a/ui/android/java/src/org/chromium/ui/base/ViewRoot.java
+++ b/ui/android/java/src/org/chromium/ui/base/ViewRoot.java
@@ -9,24 +9,28 @@ import org.chromium.base.annotations.JNINamespace;
 
 /**
  * Class used to forward view, input events down to native.
- *
- * TODO(jinsukkim): Add its native counterpart inheriting from ViewAndroid
- *     so that it will act as a root of ViewAndroid tree. It effectively
- *     replaces WindowAndroid in terms of the role.
  */
 @JNINamespace("ui")
 public class ViewRoot {
-    // The corresponding native ViewAndroid. This object can only be used while
+
+    private final WindowAndroid mWindowAndroid;
+
+    // The corresponding native instance. This class can only be used while
     // the native instance is alive.
     private long mNativeView;
 
-    @CalledByNative
-    private static ViewRoot create(long nativeView) {
-        return new ViewRoot(nativeView);
+    public static ViewRoot create(WindowAndroid window) {
+        if (window == null) throw new IllegalArgumentException("WindowAndroid should not be null");
+        return new ViewRoot(window);
     }
 
-    private ViewRoot(long nativeView) {
-        mNativeView = nativeView;
+    private ViewRoot(WindowAndroid window) {
+        mNativeView = nativeInit(window == null ? 0 : window.getNativePointer());

[boliu, 2017/01/05 19:09:29]

don't need null check here anymore

[Jinsuk Kim, 2017/01/05 22:30:15]

Done.

+        mWindowAndroid = window;
+    }
+
+    public WindowAndroid getWindowAndroid() {
+        return mWindowAndroid;
     }
 
     /**
@@ -41,10 +45,17 @@ public class ViewRoot {
     }
 
     @CalledByNative

[boliu, 2017/01/05 19:09:29]

Remove ViewRoot::FromJavaObject entirely, and then this won't be needed anymore

[Jinsuk Kim, 2017/01/05 22:30:15]

Now it's used to pass native pointer through CVC nativeInit(). Ended up taking
off @CalledByNative only.

-    private void onDestroyNativeView() {
+    public long getNativePtr() {
+        return mNativeView;
+    }
+
+    public void destroy() {

[boliu, 2017/01/05 19:09:29]

assert mNativeView != 0

[Jinsuk Kim, 2017/01/05 22:30:15]

Done.

+        nativeDestroy(mNativeView);
         mNativeView = 0;
     }
 
-    private static native void nativeOnPhysicalBackingSizeChanged(long viewAndroid,
+    private native long nativeInit(long windowNativePointer);
+    private native void nativeDestroy(long nativeViewRoot);
+    private native void nativeOnPhysicalBackingSizeChanged(long nativeViewRoot,
             int width, int height);
 }