Implemented ForceMaximizeBrowserWindowOnFirstRun policy, added unit test and browser test.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index bd6bd52aaf279d4286a3bc68291c295270b2e8c4..2393953e42c0881c33ce4ebdd9e48d5979b26fd9 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -817,6 +817,11 @@ const char kWakeOnWifiSsid[] = "settings.internet.wake_on_wifi_ssid";
 // which allows to bypass the user's proxy for captive portal authentication.
 const char kCaptivePortalAuthenticationIgnoresProxy[] =
     "proxy.captive_portal_ignores_proxy";
+
+// This boolean controls whether the first window shown on first run should be
+// unconditionally maximized, overriding the heuristic that normally chooses the
+// window size.
+const char kForceMaximizeOnFirstRun[] = "ui.force_maximize_on_first_run";
 #endif  // defined(OS_CHROMEOS)
 
 // The disabled messages in IPC logging.