Three way experiment for "Show saved copy" button.

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index d3e8e0d53116cdbc0d0945946929898bfcae7d4e..34a38391a8b466ee7ac8f54f824a5ac01d821619 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -1408,24 +1408,29 @@ void ChromeContentBrowserClient::AppendExtraCommandLineSwitches(
     }
 
     {
-      // Enable load stale cache if this session is in the field trial or
-      // the user explicitly enabled it.  Note that as far as the renderer
-      // is concerned, the feature is enabled if-and-only-if the
-      // kEnableOfflineLoadStaleCache flag is on the command line;
-      // the yes/no/default behavior is only at the browser command line
-      // level.
+      // Enable showing a saved copy if this session is in the field trial
+      // or the user explicitly enabled it.  Note that as far as the
+      // renderer is concerned, the feature is enabled if-and-only-if
+      // one of the kEnableShowSavedCopy* switches is on the command
+      // line; the yes/no/default behavior is only at the browser
+      // command line level.
 
       // Command line switches override
       if (browser_command_line.HasSwitch(
-              switches::kEnableOfflineLoadStaleCache)) {
-        command_line->AppendSwitch(switches::kEnableOfflineLoadStaleCache);
+              switches::kEnableShowSavedCopyPrimary)) {

[mmenke, 2015/02/27 20:27:14]

Maybe switch to a single switch with 3 different values?  Also, can't field
trials now set switches, either through finch, or about_flags.h, or something?

Then you'd just need to add one switch to kSwitchNames below, and remove this
entire block of code, I believe.

[megjablon, 2015/02/27 22:41:57]

I changed it to a single switch with 3 values. I couldn't find a way to set
switches through field trials, but I can keep looking around. I could move all
the logic for the field trials into localized_error.cc so that we check the
switches and then the field trial there.

+        command_line->AppendSwitch(switches::kEnableShowSavedCopyPrimary);
+      } else if (browser_command_line.HasSwitch(
+              switches::kEnableShowSavedCopySecondary)) {
+        command_line->AppendSwitch(switches::kEnableShowSavedCopySecondary);
       } else if (!browser_command_line.HasSwitch(
-          switches::kDisableOfflineLoadStaleCache)) {
+          switches::kDisableShowSavedCopy)) {
         std::string group =
             base::FieldTrialList::FindFullName("LoadStaleCacheExperiment");
 
-        if (group == "Enabled")
-          command_line->AppendSwitch(switches::kEnableOfflineLoadStaleCache);
+        if (group == "Primary")
+          command_line->AppendSwitch(switches::kEnableShowSavedCopyPrimary);
+        else if (group == "Secondary")
+          command_line->AppendSwitch(switches::kEnableShowSavedCopySecondary);
       }
     }