[embedder] Update flutter engine revision and add git fetch to sync
artifacts script

Change-Id: I15fa158479621d266b1d69133a842a6c86677cd5
diff --git a/scripts/sync_engine_artifacts_to_revision.sh b/scripts/sync_engine_artifacts_to_revision.sh
index 15c1919..c1a63c8 100755
--- a/scripts/sync_engine_artifacts_to_revision.sh
+++ b/scripts/sync_engine_artifacts_to_revision.sh
@@ -42,6 +42,7 @@
 # Sync Flutter to specified revision.
 echo-info "Syncing ${ENGINE_DIR}/flutter to ${engine_revision}..."
 pushd flutter
+git fetch upstream
 git checkout "${engine_revision}"
 popd  # flutter
 
diff --git a/src/embedder/engine/debug_x64/libflutter_engine.so b/src/embedder/engine/debug_x64/libflutter_engine.so
index 12be61f..9ea9ac0 100755
--- a/src/embedder/engine/debug_x64/libflutter_engine.so
+++ b/src/embedder/engine/debug_x64/libflutter_engine.so
Binary files differ
diff --git a/src/embedder/engine/engine_revision b/src/embedder/engine/engine_revision
index 774d8f0..cb7cfe1 100644
--- a/src/embedder/engine/engine_revision
+++ b/src/embedder/engine/engine_revision
@@ -1 +1 @@
-48f9f1fe2db6d5d13d60de020df4e857c9ff61b8
+a14b29e1b234a050eee8c987c7205f6605673f45
diff --git a/third_party/dart-pkg/internal/flutter/flutter b/third_party/dart-pkg/internal/flutter/flutter
index 8b36f4f..9853d88 160000
--- a/third_party/dart-pkg/internal/flutter/flutter
+++ b/third_party/dart-pkg/internal/flutter/flutter
@@ -1 +1 @@
-Subproject commit 8b36f4fb07c70090c2188a1808710a10044592c9
+Subproject commit 9853d886ab75f4de7f7eb970f7ef562b00123041