Factor out ContentViewAndroidDelegate

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

Index: ui/android/java/src/org/chromium/ui/base/ViewAndroid.java
diff --git a/ui/android/java/src/org/chromium/ui/base/ViewAndroid.java b/ui/android/java/src/org/chromium/ui/base/ViewAndroid.java
new file mode 100644
index 0000000000000000000000000000000000000000..5d383a0d2079d0431c06a5c04ec1fb4c5a8d3220
--- /dev/null
+++ b/ui/android/java/src/org/chromium/ui/base/ViewAndroid.java
@@ -0,0 +1,52 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.base;
+
+import android.content.Context;
+import android.view.View;
+
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+/**
+* Java counterpart for native ViewAndroid.
+*/
+@JNINamespace("ui")
+public class ViewAndroid {
+
+    private final Context mContext;
+    private final ViewAndroidDelegate mViewDelegate;

[no sievers, 2016/07/14 23:14:32]

Do you think it's possible to not have this class and have view_android.cc call
into ViewAndroidDelegate instead?

Just for the sake of keeping the interface very explicitly one-directional
(delegate up to Java).
For things that need to eventually call down into native (let's say touch
events) I was hoping we could then just also have a different interface (let's
say EventHandler or so) that ViewAndroid implements.

[Jinsuk Kim, 2016/07/15 05:46:26]

I'm not sure... ViewAndroidDelegate can be overriden, for which we need to
invoke the overriden method not having view_android.cc call
Java_ViewAndroidDelegate_xxx. 

[no sievers, 2016/07/15 18:35:00]

I think that would call the correct overloaded function through JNI.
I *think* you might be able to just generate ViewAndroidDelegate_Jni.h and then
include that in the view_android.cc file.

[Jinsuk Kim, 2016/07/18 06:45:46]

Done. I tried to annotate the overriden methods of AwViewAndroidDelegate with
@CalledByNative but couldn't since jni generator complained.

+
+    private ViewAndroid(Context context, ViewAndroidDelegate delegate) {

[no sievers, 2016/07/14 23:14:32]

You can actually get the right context from WindowAndroid.getContext
(ViewAndroid::GetWindowAndroid()).

[Jinsuk Kim, 2016/07/15 05:46:26]

Nice! Removed the context passed from ContentViewCore to native.

+        mContext = context;
+        mViewDelegate = delegate;
+    }
+
+    @CalledByNative
+    private static ViewAndroid create(Context context, ViewAndroidDelegate delegate) {
+        return new ViewAndroid(context, delegate);
+    }
+
+    @CalledByNative
+    private View acquireAnchorView() {
+        View anchorView = new View(mContext);
+        mViewDelegate.addView(anchorView);
+        return anchorView;
+    }
+
+    @CalledByNative
+    private void setAnchorViewPosition(View anchorView, float x, float y, float width, float height,
+            float scale, int leftMargin, int topMargin) {
+        if (width > 0.f && height > 0.f) {
+            mViewDelegate.setViewPosition(anchorView, x, y, width, height, scale, leftMargin,
+                    topMargin);
+        }
+    }
+
+    @CalledByNative
+    private void removeAnchorView(View anchorView) {
+        mViewDelegate.removeView(anchorView);
+    }
+}