Use better group names for zram field trial

chrome/browser/chromeos/chrome_browser_main_chromeos.cc

Index: chrome/browser/chromeos/chrome_browser_main_chromeos.cc
diff --git a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
index cb8018cda1d91677d6120294d33e791592539b38..45b3146c4335007f45bd4599611d86e852ccb213 100644
--- a/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
+++ b/chrome/browser/chromeos/chrome_browser_main_chromeos.cc
@@ -780,27 +780,29 @@ void ChromeBrowserMainPartsChromeos::SetupZramFieldTrial() {
   // newline.  "x" means the user has opted out.  "0" through "8" are the valid
   // group names.  (See src/platform/init/swap-exp.conf in chromiumos repo for
   // group meanings.)
-  std::string zram_group = zram_file_content.substr(0, 1);
-  if (zram_group.compare("x") == 0)
+  char zram_group = zram_file_content[0];

[Alexei Svitkine (slow), 2013/01/09 19:00:36]

Can you check that !zram_file_content.empty() somewhere before this?

[Alexei Svitkine (slow), 2013/01/09 19:01:24]

Sorry, I wrote this before you addressed James' comment.

+  if (zram_group == 'x')
     return;
+  if (zram_group < '0' || zram_group > '8') {
+    LOG(WARNING) << "zram field trial: invalid group \"" << zram_group << "\"";
+    return;
+  }
+  LOG(WARNING) << "zram field trial: group " << zram_group;

[Alexei Svitkine (slow), 2013/01/09 19:00:36]

field_trial.cc has VLOGs that can tell you this already, so you don't need a
separate one (unless vlog doesn't work for you).

[Luigi Semenzato, 2013/01/09 19:15:49]

We discussed this in the previous review.  That's a DVLOG(1) but for ease of
analyzing crashes etc. we want to always have this information in the Chrome OS
logs, since it's only one line per Chrome start.  This only affects Chrome OS,
not even the chromeos linux tests.

   const base::FieldTrial::Probability kDivisor = 1;  // on/off only
   scoped_refptr<base::FieldTrial> trial =
       base::FieldTrialList::FactoryGetFieldTrial(
           "ZRAM", kDivisor, "default", 2013, 12, 31, NULL);
   // Assign probability of 1 to the group Chrome OS has picked.  Assign 0 to
   // all other choices.
-  const char* const kGroups[] = { "0", "1", "2", "3", "4", "5", "6", "7", "8" };
-  bool matched = false;
-  for (size_t i = 0; i < arraysize(kGroups); ++i) {
-    bool match = zram_group.compare(kGroups[i]) == 0;
-    trial->AppendGroup(kGroups[i], match ? 1 : 0);
-    if (match) {
-      matched = true;
-      LOG(WARNING) << "zram field trial: group " << kGroups[i];
-    }
-  }
-  if (!matched)
-    LOG(WARNING) << "zram field trial: invalid group \"" << zram_group << "\"";
+  trial->AppendGroup("2GB RAM, no swap", zram_group == '0' ? 1 : 0);
+  trial->AppendGroup("2GB RAM, 2GB swap", zram_group == '1' ? 1 : 0);
+  trial->AppendGroup("2GB RAM, 3GB swap", zram_group == '2' ? 1 : 0);
+  trial->AppendGroup("4GB RAM, no swap", zram_group == '3' ? 1 : 0);
+  trial->AppendGroup("4GB RAM, 4GB swap", zram_group == '4' ? 1 : 0);
+  trial->AppendGroup("4GB RAM, 6GB swap", zram_group == '5' ? 1 : 0);
+  trial->AppendGroup("snow, no swap", zram_group == '6' ? 1 : 0);
+  trial->AppendGroup("snow, 1GB swap", zram_group == '7' ? 1 : 0);
+  trial->AppendGroup("snow, 2GB swap", zram_group == '8' ? 1 : 0);
 }
 
 }  //  namespace chromeos