Port perf.py's _LoginToGoogleAccount to chrome_remote_control

tools/gpu/page_sets/credentials.json

Index: tools/gpu/page_sets/credentials.json
diff --git a/tools/gpu/page_sets/credentials.json b/tools/gpu/page_sets/credentials.json
new file mode 100644
index 0000000000000000000000000000000000000000..6ede6ffa747846a21c16506057fa76309731146d
--- /dev/null
+++ b/tools/gpu/page_sets/credentials.json
@@ -0,0 +1,6 @@
+{
+  "google_username": null,
+  "google_password": null,

[tonyg, 2012/09/24 20:41:01]

are we really going to check the password into the public repo? Seems more
appropriate for src-internal.

[nduca, 2012/09/24 20:50:00]

I think this is just an example file to document how this works with the intent
that we have a real file in src-internal that we pull in. Maybe we should add
some notes here. Maybe we should call this empty_credentials.json and a
companion file, credentials_format.txt explaining the format?

[dtu, 2012/09/24 21:35:10]

I think the script should check this file first and fall back to the internal
file. Then public contributors can put their own credentials in this file to run
the test. So empty_credentials.json is not a good name, but a comment would be
useful telling people how to use this file.

+
+  "google_account_url": null
+}