[ChromeDriver] Rename send_command_and_get_result to proper extension

This CL renames the send_command_and_get_result endpoint to
/goog/cdp/execute which follows the extension specification format
and is a more appropriate API name. Note we still support the old name.

Bug: chromedriver:2307
Change-Id: Ia7a389781eb92a2cf9bd6244e766e6c32e9b5ab9
Reviewed-on: https://chromium-review.googlesource.com/1091216Reviewed-by: John Chen <johnchen@chromium.org>
Commit-Queue: Jonathon Kereliuk <kereliuk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565356}

chrome/test/chromedriver/server/http_handler.cc

@@ -562,6 +562,9 @@ HttpHandler::HttpHandler(
       CommandMapping(
           kPost, "session/:sessionId/chromium/send_command",
           WrapToCommand("SendCommand", base::Bind(&ExecuteSendCommand))),
+      CommandMapping(
+          kPost, "session/:sessionId/goog/cdp/execute",
+          WrapToCommand("ExecuteCDP", base::Bind(&ExecuteSendCommandAndGetResult))),
       CommandMapping(
           kPost, "session/:sessionId/chromium/send_command_and_get_result",
           WrapToCommand("SendCommandAndGetResult",