android webview: Keep zoom methods synchronous

content/browser/android/in_process/synchronous_compositor_impl.cc

Index: content/browser/android/in_process/synchronous_compositor_impl.cc
diff --git a/content/browser/android/in_process/synchronous_compositor_impl.cc b/content/browser/android/in_process/synchronous_compositor_impl.cc
index 1b06e510faaf0824d5b8e2bbe1f6162306427f78..aa0a23bd9818ddf721cc76397c8f99b427f39f8e 100644
--- a/content/browser/android/in_process/synchronous_compositor_impl.cc
+++ b/content/browser/android/in_process/synchronous_compositor_impl.cc
@@ -253,6 +253,10 @@ void SynchronousCompositorImpl::SetIsActive(bool is_active) {
     begin_frame_source_->SetBeginFrameSourcePaused(!is_active_);
 }
 
+void SynchronousCompositorImpl::SynchronizeWithRenderer() {
+  // Intentional no-op. Nothing to synchronize.
+}
+
 void SynchronousCompositorImpl::OnComputeScroll(
     base::TimeTicks animation_time) {
   if (need_animate_input_) {