[WebView] Add a new flushVisualState API to AwContents.

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

 // Copyright 2012 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.android_webview;
 
 import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.ComponentCallbacks2;
 import android.content.Context;
@@ skipping 163 matching lines @@
         public AwLayoutSizer createLayoutSizer() {
             return new AwLayoutSizer();
         }
 
         public AwScrollOffsetManager createScrollOffsetManager(
                 AwScrollOffsetManager.Delegate delegate, OverScroller overScroller) {
             return new AwScrollOffsetManager(delegate, overScroller);
         }
     }
 
+    /**
+     * Callback used when flushing the visual state, see {@link #flushVisualState}.
+     */
+    @VisibleForTesting
+    public abstract static class VisualStateFlushCallback {
+        public abstract void onComplete();
+        public abstract void onFailure();
+    }
+
     private long mNativeAwContents;
     private final AwBrowserContext mBrowserContext;
     private ViewGroup mContainerView;
     private final AwLayoutChangeListener mLayoutChangeListener;
     private final Context mContext;
     private ContentViewCore mContentViewCore;
     private WindowAndroid mWindowAndroid;
     private WebContents mWebContents;
     private NavigationController mNavigationController;
     private final AwContentsClient mContentsClient;
@@ skipping 1828 matching lines @@
     public void hideAutofillPopup() {
         if (mAwAutofillClient != null) {
             mAwAutofillClient.hideAutofillPopup();
         }
     }
 
     public void setNetworkAvailable(boolean networkUp) {
         if (!isDestroyed()) nativeSetJsOnlineProperty(mNativeAwContents, networkUp);
     }
 
+    /**
+     * Flush the visual state.
+     *
+     * Flushing the visual state means queuing a callback in Blink that will be invoked when the
+     * contents of the DOM tree at the moment that the callback was enqueued (or later) are drawn
+     * into the screen. In other words, the following events need to happen before the callback is
+     * invoked:
+     * 1. The DOM tree is committed becoming the pending tree - see ThreadProxy::BeginMainFrame
+     * 2. The pending tree is activated becoming the active tree
+     * 3. A frame swap happens that draws the active tree into the screen
+     */
+    public void flushVisualState(VisualStateFlushCallback callback) {
+        nativeFlushVisualState(mNativeAwContents, callback);
+    }
+
     //--------------------------------------------------------------------------------------------
     //  Methods called from native via JNI
     //--------------------------------------------------------------------------------------------
 
     @CalledByNative
     private static void onDocumentHasImagesResponse(boolean result, Message message) {
         message.arg1 = result ? 1 : 0;
         message.sendToTarget();
     }
 
@@ skipping 83 matching lines @@
     }
 
     @CalledByNative
     public void onNewPicture() {
         // Don't call capturePicture() here but instead defer it until the posted task runs within
         // the callback helper, to avoid doubling back into the renderer compositor in the middle
         // of the notification it is sending up to here.
         mContentsClient.getCallbackHelper().postOnNewPicture(mPictureListenerContentProvider);
     }
 
+    /**
+     * Invokes the given {@link VisualStateFlushCallback}.
+     *
+     * @param result true if the flush request was successful and false otherwise
+     */
+    @CalledByNative
+    public void flushVisualStateCallback(
+            final VisualStateFlushCallback callback, final boolean result) {
+        // Posting avoids invoking the callback inside invoking_composite_
+        // (see synchronous_compositor_impl.cc and crbug/452530).
+        mContainerView.getHandler().post(new Runnable() {
+            @Override
+            public void run() {
+                if (result) {
+                    callback.onComplete();
+                } else {
+                    callback.onFailure();
+                }
+            }
+        });
+    }
+
     // Called as a result of nativeUpdateLastHitTestData.
     @CalledByNative
     private void updateHitTestData(
             int type, String extra, String href, String anchorText, String imgSrc) {
         mPossiblyStaleHitTestData.hitTestResultType = type;
         mPossiblyStaleHitTestData.hitTestResultExtraData = extra;
         mPossiblyStaleHitTestData.href = href;
         mPossiblyStaleHitTestData.anchorText = anchorText;
         mPossiblyStaleHitTestData.imgSrc = imgSrc;
     }
@@ skipping 536 matching lines @@
     // Returns false if restore state fails.
     private native boolean nativeRestoreFromOpaqueState(long nativeAwContents, byte[] state);
 
     private native long nativeReleasePopupAwContents(long nativeAwContents);
     private native void nativeFocusFirstNode(long nativeAwContents);
     private native void nativeSetBackgroundColor(long nativeAwContents, int color);
 
     private native long nativeGetAwDrawGLViewContext(long nativeAwContents);
     private native long nativeCapturePicture(long nativeAwContents, int width, int height);
     private native void nativeEnableOnNewPicture(long nativeAwContents, boolean enabled);
+    private native void nativeFlushVisualState(
+            long nativeAwContents, VisualStateFlushCallback callback);
     private native void nativeClearView(long nativeAwContents);
     private native void nativeSetExtraHeadersForUrl(long nativeAwContents,
             String url, String extraHeaders);
 
     private native void nativeInvokeGeolocationCallback(
             long nativeAwContents, boolean value, String requestingFrame);
 
     private native void nativeSetJsOnlineProperty(long nativeAwContents, boolean networkUp);
 
     private native void nativeTrimMemory(long nativeAwContents, int level, boolean visible);
 
     private native void nativeCreatePdfExporter(long nativeAwContents, AwPdfExporter awPdfExporter);
 
     private native void nativePreauthorizePermission(long nativeAwContents, String origin,
             long resources);
 
     private native void nativePostMessageToFrame(long nativeAwContents, String frameId,
             String message, String sourceOrigin, String targetOrigin, int[] msgPorts);
 
     private native void nativeCreateMessageChannel(long nativeAwContents,
             ValueCallback<MessageChannel> callback);
 }