Reparent surface control for Webview overlay

When the root surface control changes, the parent of the Webview surface control must be changed.

Bug: 191900007
Test: switch app, or turn on/off screen
Change-Id: Ib7b34133776fd5944afc638bfee471afe6a17349
diff --git a/libs/hwui/renderthread/RenderThread.cpp b/libs/hwui/renderthread/RenderThread.cpp
index 524407d..f83c0a4 100644
--- a/libs/hwui/renderthread/RenderThread.cpp
+++ b/libs/hwui/renderthread/RenderThread.cpp
@@ -98,6 +98,10 @@
     LOG_ALWAYS_FATAL_IF(transactionApplyFunc == nullptr,
                         "Failed to find required symbol ASurfaceTransaction_apply!");
 
+    transactionReparentFunc = (AST_reparent)dlsym(handle_, "ASurfaceTransaction_reparent");
+    LOG_ALWAYS_FATAL_IF(transactionReparentFunc == nullptr,
+                        "Failed to find required symbol transactionReparentFunc!");
+
     transactionSetVisibilityFunc =
             (AST_setVisibility)dlsym(handle_, "ASurfaceTransaction_setVisibility");
     LOG_ALWAYS_FATAL_IF(transactionSetVisibilityFunc == nullptr,