From 59c2536d34bf345fbbef29dc70656e879eba32e2 Mon Sep 17 00:00:00 2001
From: Jason Simmons <jason-simmons@users.noreply.github.com>
Date: Wed, 29 Nov 2017 10:55:45 -0800
Subject: [PATCH] Set a pending dimension change in the animator only if the
 viewport's physical width/height changed (flutter/engine#4400)

Fixes https://github.com/flutter/flutter/issues/13183
---
 engine/src/flutter/shell/common/engine.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/engine/src/flutter/shell/common/engine.cc b/engine/src/flutter/shell/common/engine.cc
index 6bb5977ac13..9372f7baa4a 100644
--- a/engine/src/flutter/shell/common/engine.cc
+++ b/engine/src/flutter/shell/common/engine.cc
@@ -343,11 +343,15 @@ void Engine::OnOutputSurfaceDestroyed(const fxl::Closure& gpu_continuation) {
 }
 
 void Engine::SetViewportMetrics(const blink::ViewportMetrics& metrics) {
+  bool dimensions_changed =
+      viewport_metrics_.physical_height != metrics.physical_height ||
+      viewport_metrics_.physical_width != metrics.physical_width;
   viewport_metrics_ = metrics;
   if (runtime_)
     runtime_->SetViewportMetrics(viewport_metrics_);
   if (animator_) {
-    animator_->SetDimensionChangePending();
+    if (dimensions_changed)
+      animator_->SetDimensionChangePending();
     if (have_surface_)
       ScheduleFrame();
   }