[chromedriver] Implement command: switchToWindow.

chrome/test/chromedriver/session_commands.h

Index: chrome/test/chromedriver/session_commands.h
diff --git a/chrome/test/chromedriver/session_commands.h b/chrome/test/chromedriver/session_commands.h
index 259bf8898f4d65b9474c26c2777f34f1922739a1..0596e779c013805abbb80802110a1d5f084fb2b3 100644
--- a/chrome/test/chromedriver/session_commands.h
+++ b/chrome/test/chromedriver/session_commands.h
@@ -54,6 +54,13 @@ Status ExecuteGetWindowHandles(
     const base::DictionaryValue& params,
     scoped_ptr<base::Value>* value);
 
+// Change target window to another. The window to target at may be specified by
+// its server assigned window handle, or by the value of its name attribute.
+Status ExecuteSwitchToWindow(
+    Session* session,
+    const base::DictionaryValue& params,
+    scoped_ptr<base::Value>* value);
+
 // Configure the amount of time that a particular type of operation can execute
 // for before they are aborted and a timeout error is returned to the client.
 Status ExecuteSetTimeout(