Implement window management devtools commands for headless.

headless/lib/browser/headless_browser_impl.cc

Index: headless/lib/browser/headless_browser_impl.cc
diff --git a/headless/lib/browser/headless_browser_impl.cc b/headless/lib/browser/headless_browser_impl.cc
index 57605807d53a9488123ae1ca0d000934b2ff4067..316a5a61cde9f63de2f366c8082471f561801b6b 100644
--- a/headless/lib/browser/headless_browser_impl.cc
+++ b/headless/lib/browser/headless_browser_impl.cc
@@ -63,11 +63,21 @@ int RunContentMain(
 
 }  // namespace
 
+HeadlessBrowserWindow::HeadlessBrowserWindow(gfx::Size size)
+    : bounds_(size), state_("normal") {}
+
+void HeadlessBrowserWindow::set_state(std::string state) {
+  DCHECK(state == "normal" || state == "minimized" || state == "maximized" ||
+         state == "fullscreen");
+  state_ = state;
+}
+
 HeadlessBrowserImpl::HeadlessBrowserImpl(
     const base::Callback<void(HeadlessBrowser*)>& on_start_callback,
     HeadlessBrowser::Options options)
     : on_start_callback_(on_start_callback),
       options_(std::move(options)),
+      window_(options_.window_size),
       browser_main_parts_(nullptr),
       default_browser_context_(nullptr),
       agent_host_(nullptr),