Surface Synchronization: Only defer commits if frame exists

Right now, with surface sync off on Android, we will defer commits
any time there's a size change, even if we've evicted the current
surface.

Change-Id: I7e1ae394e20eef2a46bca5ae9a8fc8a4cdf35e0b
Bug: 848292, 672962
Reviewed-on: https://chromium-review.googlesource.com/1121098Reviewed-by: Saman Sami <samans@chromium.org>
Reviewed-by: Khushal <khushalsagar@chromium.org>
Commit-Queue: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575405}

ui/android/delegated_frame_host_android.cc

@@ -320,7 +320,7 @@ void DelegatedFrameHostAndroid::PixelSizeWillChange(
 
   expected_pixel_size_ = pixel_size;
   if (registered_parent_compositor_) {
-    if (content_layer_->bounds() != expected_pixel_size_) {
+    if (HasSavedFrame() && content_layer_->bounds() != expected_pixel_size_) {
       compositor_pending_resize_lock_ =
           registered_parent_compositor_->GetCompositorLock(
               this, base::TimeDelta::FromSeconds(kResizeTimeoutSeconds));