Revert r155813 "Reland - cros: Add chat icon to app list"

chrome/common/extensions/extension_constants.h

Index: chrome/common/extensions/extension_constants.h
diff --git a/chrome/common/extensions/extension_constants.h b/chrome/common/extensions/extension_constants.h
index e00658b446aa98dff4d5397adb9dc89b7a6dc24f..2c0606f4ca6ca803de643e29bd1e19187e2c2b94 100644
--- a/chrome/common/extensions/extension_constants.h
+++ b/chrome/common/extensions/extension_constants.h
@@ -115,12 +115,6 @@ namespace extension_misc {
   // The extension id of the Chrome component application.
   extern const char kChromeAppId[];
 
-  // The extension ids of the various versions of the Talk extension.
-  extern const char kTalkExtensionId[];
-  extern const char kTalkBetaExtensionId[];
-  extern const char kTalkAlphaExtensionId[];
-  extern const char kTalkDebugExtensionId[];
-
   // Note: this structure is an ASN.1 which encodes the algorithm used
   // with its parameters. This is defined in PKCS #1 v2.1 (RFC 3447).
   // It is encoding: { OID sha1WithRSAEncryption      PARAMETERS NULL }