android webview: Keep zoom methods synchronous

android_webview/native/aw_contents.cc

 // 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.
 
 #include "android_webview/native/aw_contents.h"
 
 #include <limits>
 #include <utility>
 
 #include "android_webview/browser/aw_browser_context.h"
@@ skipping 997 matching lines @@
   web_contents_->FocusThroughTabTraversal(false);
 }
 
 void AwContents::SetBackgroundColor(JNIEnv* env,
                                     const JavaParamRef<jobject>& obj,
                                     jint color) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   render_view_host_ext_->SetBackgroundColor(color);
 }
 
+void AwContents::SynchronizeRendererScroll(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj) {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  browser_view_renderer_.SynchronizeRendererScroll();
+}
+
 void AwContents::OnComputeScroll(JNIEnv* env,
                                  const JavaParamRef<jobject>& obj,
                                  jlong animation_time_millis) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   browser_view_renderer_.OnComputeScroll(
       base::TimeTicks() +
       base::TimeDelta::FromMilliseconds(animation_time_millis));
 }
 
 jlong AwContents::ReleasePopupAwContents(JNIEnv* env,
@@ skipping 276 matching lines @@
     const JavaParamRef<jobject>& obj) {
   web_contents_->ResumeLoadingCreatedWebContents();
 }
 
 void SetShouldDownloadFavicons(JNIEnv* env,
                                const JavaParamRef<jclass>& jclazz) {
   g_should_download_favicons = true;
 }
 
 }  // namespace android_webview