Introduce ViewRoot forwarding input/view events to native

android_webview/java/src/org/chromium/android_webview/AwContents.java

Index: android_webview/java/src/org/chromium/android_webview/AwContents.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwContents.java b/android_webview/java/src/org/chromium/android_webview/AwContents.java
index f868572acdf78ff9beea53b8581a82c4d16136e4..ac2e65cad39836f51c175f8f5a18c92f9c1ac0e9 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContents.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContents.java
@@ -812,8 +812,8 @@ public class AwContents implements SmartClipProvider, PostMessageSender.PostMess
             Context context, ViewAndroidDelegate viewDelegate,
             InternalAccessDelegate internalDispatcher, WebContents webContents,
             GestureStateListener gestureStateListener, ContentViewClient contentViewClient,
-            WindowAndroid windowAndroid) {
-        contentViewCore.initialize(viewDelegate, internalDispatcher, webContents, windowAndroid);
+            WindowAndroid windowAndroid, ViewRoot viewRoot) {
+        contentViewCore.initialize(viewDelegate, internalDispatcher, webContents, viewRoot);
         contentViewCore.setActionModeCallback(
                 new AwActionModeCallback(mContext, this,
                         contentViewCore.getActionModeCallbackHelper()));
@@ -1056,9 +1056,10 @@ public class AwContents implements SmartClipProvider, PostMessageSender.PostMess
         mContentViewCore = new ContentViewCore(mContext, PRODUCT_VERSION);
         mViewAndroidDelegate = new AwViewAndroidDelegate(mContainerView,
                 mContentViewCore.getRenderCoordinates());
+        mViewRoot = ViewRoot.create(mWindowAndroid.getWindowAndroid());
         initializeContentViewCore(mContentViewCore, mContext, mViewAndroidDelegate,
                 mInternalAccessAdapter, webContents, new AwGestureStateListener(),
-                mContentViewClient, mWindowAndroid.getWindowAndroid());
+                mContentViewClient, mWindowAndroid.getWindowAndroid(), mViewRoot);
         nativeSetJavaPeers(mNativeAwContents, this, mWebContentsDelegate, mContentsClientBridge,
                 mIoThreadClient, mInterceptNavigationDelegate);
         mWebContents = mContentViewCore.getWebContents();
@@ -1202,6 +1203,8 @@ public class AwContents implements SmartClipProvider, PostMessageSender.PostMess
             mWebContentsObserver = null;
             mContentViewCore.destroy();
             mContentViewCore = null;
+            mViewRoot.destroy();

[boliu, 2017/01/05 19:09:28]

Finding the right place to call destroy is tricky for webview. This doesn't work
if webview is garbage collected without being destroyed first (which is
allowed..) The right place to handle that is pass the ViewRoot into
AwContentsDestroyRunnable, and call destroy in run()

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

Done. I'm still keeping the code nulling out mViewRoot below in this case where
mCleanupReference is not set.

+            mViewRoot = null;
             mNativeAwContents = 0;
             mWebContents = null;
             mNavigationController = null;
@@ -3209,7 +3212,7 @@ public class AwContents implements SmartClipProvider, PostMessageSender.PostMess
             // to enter fixedLayoutSize mode is sent before the first resize
             // update.
             mLayoutSizer.onSizeChanged(w, h, ow, oh);
-            getViewRoot().onPhysicalBackingSizeChanged(w, h);
+            mViewRoot.onPhysicalBackingSizeChanged(w, h);
             mContentViewCore.onSizeChanged(w, h, ow, oh);
             nativeOnSizeChanged(mNativeAwContents, w, h, ow, oh);
         }
@@ -3285,13 +3288,6 @@ public class AwContents implements SmartClipProvider, PostMessageSender.PostMess
         }
     }
 
-    private ViewRoot getViewRoot() {
-        if (mViewRoot == null) {
-            mViewRoot = nativeGetViewRoot(mNativeAwContents);
-        }
-        return mViewRoot;
-    }
-
     // Return true if the GeolocationPermissionAPI should be used.
     @CalledByNative
     private boolean useLegacyGeolocationPermissionAPI() {
@@ -3395,5 +3391,4 @@ public class AwContents implements SmartClipProvider, PostMessageSender.PostMess
 
     private native void nativeGrantFileSchemeAccesstoChildProcess(long nativeAwContents);
     private native void nativeResumeLoadingCreatedPopupWebContents(long nativeAwContents);
-    private native ViewRoot nativeGetViewRoot(long nativeAwContents);
 }