Clear needs_resize_ack when clearing DeviceMetricsOverride.

content/renderer/devtools/render_widget_screen_metrics_emulator.cc

Index: content/renderer/devtools/render_widget_screen_metrics_emulator.cc
diff --git a/content/renderer/devtools/render_widget_screen_metrics_emulator.cc b/content/renderer/devtools/render_widget_screen_metrics_emulator.cc
index d5f4983f1395c563aae26b216aecdfffb69bd976..6c27f46570fe8912622ec1d850abaa1db971bd0b 100644
--- a/content/renderer/devtools/render_widget_screen_metrics_emulator.cc
+++ b/content/renderer/devtools/render_widget_screen_metrics_emulator.cc
@@ -25,6 +25,9 @@ RenderWidgetScreenMetricsEmulator::RenderWidgetScreenMetricsEmulator(
 }
 
 RenderWidgetScreenMetricsEmulator::~RenderWidgetScreenMetricsEmulator() {
+  // needs_resize_ack was handled during OnResize() and may cause a DCHECK to
+  // fail in RenderWidget if not cleared (crbug.com/635560).
+  original_resize_params_.needs_resize_ack = false;
   delegate_->Resize(original_resize_params_);
   delegate_->SetScreenMetricsEmulationParameters(false, emulation_params_);
   delegate_->SetScreenRects(original_view_screen_rect_,