Ensure an empty frame's size is non zero

This is a speculative fix for crbug.com/1041932

Bug: 1041932
Change-Id: I0dfe7479967729dc242f32eba4772107fcc3f7ca
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2093073
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Saman Sami <samans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748568}

components/exo/surface_tree_host.cc

@@ -232,7 +232,7 @@ void SurfaceTreeHost::SubmitCompositorFrame() {
     const std::string* app_id = GetShellApplicationId(toplevel);
     const std::string* startup_id = GetShellStartupId(toplevel);
     auto* shell_surface = GetShellSurfaceBaseForWindow(toplevel);
-    DCHECK(!frame.size_in_pixels().IsEmpty())
+    CHECK(!frame.size_in_pixels().IsEmpty())
         << " Title=" << shell_surface->GetWindowTitle()
         << ", AppType=" << static_cast<int>(app_type)
         << ", AppId=" << (app_id ? *app_id : "''")
@@ -339,8 +339,13 @@ viz::CompositorFrame SurfaceTreeHost::PrepareToSubmitCompositorFrame() {
   // because  the size is different.
   const float device_scale_factor =
       host_window()->layer()->device_scale_factor();
-  const gfx::Size output_surface_size_in_pixels = gfx::ConvertSizeToPixel(
+  gfx::Size output_surface_size_in_pixels = gfx::ConvertSizeToPixel(
       device_scale_factor, host_window_->bounds().size());
+  // Viz will crash if the frame size is empty. Ensure it's not empty.
+  // crbug.com/1041932.
+  if (output_surface_size_in_pixels.IsEmpty())
+    output_surface_size_in_pixels.SetSize(1, 1);
+
   render_pass->SetNew(kRenderPassId, gfx::Rect(output_surface_size_in_pixels),
                       gfx::Rect(), gfx::Transform());
   frame.metadata.device_scale_factor = device_scale_factor;