Turn on flag for Linux, too.

chrome/browser/about_flags.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/about_flags.h"
 
 #include <algorithm>
 #include <iterator>
 #include <map>
 #include <set>
@@ skipping 112 matching lines @@
     IDS_FLAGS_CONFLICTS_CHECK_NAME,
     IDS_FLAGS_CONFLICTS_CHECK_DESCRIPTION,
     kOsWin,
     SINGLE_VALUE_TYPE(switches::kConflictingModulesCheck)
   },
   {
     "cloud-print-proxy",  // FLAGS:RECORD_UMA
     IDS_FLAGS_CLOUD_PRINT_PROXY_NAME,
     IDS_FLAGS_CLOUD_PRINT_PROXY_DESCRIPTION,
 #if defined(GOOGLE_CHROME_BUILD)
-    // For a Chrome build, we know we have a PDF plug-in, and so we'll
-    // enable by platform as we get things working.
-    kOsMac,
+    // For a Chrome build, we know we have a PDF plug-in on Windows, so it's
+    // fully enabled. Mac and Linux still need some final polish.
+    kOsMac | kOsLinux,
 #else
     // Otherwise, where we know it could be working if a viable PDF
     // plug-in could be supplied, we'll keep the lab enabled.
-    kOsWin | kOsMac,
+    kOsWin | kOsMac | kOsLinux,
 #endif
     SINGLE_VALUE_TYPE(switches::kEnableCloudPrintProxy)
   },
   {
     "crxless-web-apps",
     IDS_FLAGS_CRXLESS_WEB_APPS_NAME,
     IDS_FLAGS_CRXLESS_WEB_APPS_DESCRIPTION,
     kOsAll,
     SINGLE_VALUE_TYPE(switches::kEnableCrxlessWebApps)
   },
@@ skipping 535 matching lines @@
 }
 
 const Experiment* GetExperiments(size_t* count) {
   *count = num_experiments;
   return experiments;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags