[chromedriver] Implement commands: findChildElement, findChildElements.

chrome/test/chromedriver/commands.h

Index: chrome/test/chromedriver/commands.h
diff --git a/chrome/test/chromedriver/commands.h b/chrome/test/chromedriver/commands.h
index bef095c51187fd81587e7c7b2a9fa27eadb1177e..75261f613a76890fcc28cb654999127cee99c77b 100644
--- a/chrome/test/chromedriver/commands.h
+++ b/chrome/test/chromedriver/commands.h
@@ -82,6 +82,18 @@ Status ExecuteFindElements(
     const base::DictionaryValue& params,
     scoped_ptr<base::Value>* value);
 
+// Search for an element on the page, starting from the given element.
+Status ExecuteFindChildElement(
+    Session* session,
+    const base::DictionaryValue& params,
+    scoped_ptr<base::Value>* value);
+
+// Search for multiple elements on the page, starting from the given element.
+Status ExecuteFindChildElements(
+    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(