Adding the Copresence RpcHandler and HttpPost helper.

chrome/common/chrome_switches.cc

Index: chrome/common/chrome_switches.cc
diff --git a/chrome/common/chrome_switches.cc b/chrome/common/chrome_switches.cc
index 51113d41afee63b38c607b5f2a55257c73544cf6..99527385692b4a0eaaa6ed611de2cfad2413ded9 100644
--- a/chrome/common/chrome_switches.cc
+++ b/chrome/common/chrome_switches.cc
@@ -160,6 +160,13 @@ const char kCloudPrintJobTitle[]            = "cloud-print-job-title";
 // service or register proxy for autostart.
 const char kCloudPrintSetupProxy[]          = "cloud-print-setup-proxy";
 
+// Use this address for calls to the Copresence server (via Apiary).

[Daniel Erat, 2014/08/06 00:44:46]

change to:

// Address for calls to the Copresence server etc.

[Charlie, 2014/08/06 19:32:17]

Done.

+// Defaults to https://www.googleapis.com/copresence/v2/copresence.
+const char kCopresenceServer[]              = "copresence-server";
+
+// Use this Apiary tracing token for calls to the Copresence server.

[Daniel Erat, 2014/08/06 00:44:46]

change to:

// Apiary tracing token etc.

[Charlie, 2014/08/06 19:32:17]

Done.

+const char kCopresenceTracingToken[]        = "copresence-tracing-token";
+
 // Comma-separated list of BrowserThreads that cause browser process to crash
 // if the given browser thread is not responsive. UI,IO,DB,FILE,CACHE are the
 // list of BrowserThreads that are supported.
@@ -780,10 +787,12 @@ const char kKioskMode[]                     = "kiosk";
 // See http://crbug.com/31395.
 const char kKioskModePrinting[]             = "kiosk-printing";
 
-// Use this server address ledger.
+// Use this address for the ledger (Copresence) server.

[Daniel Erat, 2014/08/06 00:44:46]

get rid of "Use this" here and in the next comment too

[Charlie, 2014/08/06 19:32:17]

Done.

+// Ledger is deprecated; use the chrome.copresence API instead.
 const char kLedgerServer[]                  = "ledger-server";
 
-// Use this tracing token for ledger.
+// Use this tracing token for calls to the ledger (Copresence) server.
+// Ledger is deprecated; use the chrome.copresence API instead.
 const char kLedgerTracingToken[]            = "ledger-tracing-token";
 
 // Causes Chrome to attempt to get metadata from the webstore for the