Implement window management devtools commands for headless.

headless/lib/browser/headless_devtools_manager_delegate.h

Index: headless/lib/browser/headless_devtools_manager_delegate.h
diff --git a/headless/lib/browser/headless_devtools_manager_delegate.h b/headless/lib/browser/headless_devtools_manager_delegate.h
index a51254746268545f91429d860d678d4f166a000a..0c699fa6e6743f1b615cc151869eb2dbea6f4f96 100644
--- a/headless/lib/browser/headless_devtools_manager_delegate.h
+++ b/headless/lib/browser/headless_devtools_manager_delegate.h
@@ -62,6 +62,15 @@ class HeadlessDevToolsManagerDelegate
   std::unique_ptr<base::DictionaryValue> DisposeBrowserContext(
       int command_id,
       const base::DictionaryValue* params);
+  std::unique_ptr<base::DictionaryValue> GetWindowForTarget(
+      int command_id,
+      const base::DictionaryValue* params);
+  std::unique_ptr<base::DictionaryValue> GetWindowBounds(
+      int command_id,
+      const base::DictionaryValue* params);
+  std::unique_ptr<base::DictionaryValue> SetWindowBounds(
+      int command_id,
+      const base::DictionaryValue* params);
   void PrintToPDF(content::DevToolsAgentHost* agent_host,
                   int command_id,
                   const base::DictionaryValue* params,