Implemented ForceMaximizeBrowserWindowOnFirstRun policy, added unit test and browser test.

chrome/browser/ui/ash/chrome_shell_delegate.cc

Index: chrome/browser/ui/ash/chrome_shell_delegate.cc
diff --git a/chrome/browser/ui/ash/chrome_shell_delegate.cc b/chrome/browser/ui/ash/chrome_shell_delegate.cc
index 88998525db8117bb5342cdda7a63554ce6da4a56..f88c6b5d709e39a18cc7ac7dcde3f309b20915c9 100644
--- a/chrome/browser/ui/ash/chrome_shell_delegate.cc
+++ b/chrome/browser/ui/ash/chrome_shell_delegate.cc
@@ -22,8 +22,13 @@
 #include "ui/base/l10n/l10n_util.h"
 
 #if defined(OS_CHROMEOS)
+#include "base/prefs/pref_service.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
 #include "chrome/browser/chromeos/display/display_configuration_observer.h"
+#include "chrome/browser/chromeos/profiles/profile_helper.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/common/pref_names.h"
+#include "components/user_manager/user.h"
 #include "components/user_manager/user_manager.h"
 #endif
 
@@ -88,6 +93,20 @@ bool ChromeShellDelegate::IsMultiAccountEnabled() const {
   return false;
 }
 
+bool ChromeShellDelegate::ForceMaximizeOnFirstRun() const {
+#if defined(OS_CHROMEOS)
+  const user_manager::User* const user =
+      user_manager::UserManager::Get()->GetActiveUser();
+  if (user) {
+    return chromeos::ProfileHelper::Get()
+        ->GetProfileByUser(user)
+        ->GetPrefs()
+        ->GetBoolean(prefs::kForceMaximizeOnFirstRun);
+  }
+#endif
+  return false;
+}
+
 void ChromeShellDelegate::Exit() {
   chrome::AttemptUserExit();
 }