add experimental param to control the triggering threshold to default Always Translate checked

components/translate/core/browser/translate_prefs.cc

Index: components/translate/core/browser/translate_prefs.cc
diff --git a/components/translate/core/browser/translate_prefs.cc b/components/translate/core/browser/translate_prefs.cc
index 83c7cc8e7ecc9253e3352199b870f05c4c1df94a..d15a76f24beb1e923cabf84236a81f7404e71a6c 100644
--- a/components/translate/core/browser/translate_prefs.cc
+++ b/components/translate/core/browser/translate_prefs.cc
@@ -7,6 +7,7 @@
 #include <set>
 
 #include "base/memory/ptr_util.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "build/build_config.h"
@@ -17,6 +18,7 @@
 #include "components/translate/core/browser/translate_download_manager.h"
 #include "components/translate/core/browser/translate_experiment.h"
 #include "components/translate/core/common/translate_util.h"
+#include "components/variations/variations_associated_data.h"
 
 namespace translate {
 
@@ -35,6 +37,9 @@ const char TranslatePrefs::kPrefTranslateLastDeniedTimeForLanguage[] =
     "translate_last_denied_time_for_language";
 const char TranslatePrefs::kPrefTranslateTooOftenDeniedForLanguage[] =
     "translate_too_often_denied_for_language";
+const char kTranslateUI2016Q2TrialName[] = "TranslateUI2016Q2";
+const char kNumOfTranslationTriggerAlways[] =
+    "num_of_translation_trigger_always";
 
 // The below properties used to be used but now are deprecated. Don't use them
 // since an old profile might have some values there.
@@ -448,6 +453,34 @@ bool TranslatePrefs::ShouldAutoTranslate(const std::string& original_language,
   return false;
 }
 
+bool TranslatePrefs::ShouldAlwaysTranslateBeCheckedByDefault(

[groby-ooo-7-16, 2016/06/27 23:00:34]

This is moving even more policy decisions into prefs. When will we start moving
them out instead?

[ftang, 2016/06/28 05:01:46]

moved

+    const std::string& language) {
+  std::map<std::string, std::string> params;
+  int num_of_translation_trigger_default_checked = -1;

[groby-ooo-7-16, 2016/06/27 23:00:34]

StringToInt *will* force this to 0 on error.

[ftang, 2016/06/28 05:01:46]

Done.

+  if (variations::GetVariationParams(translate::kTranslateUI2016Q2TrialName,
+                                     &params)) {
+    std::map<std::string, std::string>::const_iterator it =

[groby-ooo-7-16, 2016/06/27 23:00:34]

auto it = params.find 

Or, if you want even shorter,
if (!variations::GetVariationsParam(...))
  return false;

base::StringToInt(params[translate::kNumOfTranslationTriggerAlways],
&threshold);
if (threshold <= 0)
  return false;

return GetTranslationAcceptedCount(language) >= threshold;


(Auto-creation of map members guarantees an empty string if the key is not
found, StringToInt will set Threshold to 0 when invalid or empty)

[ftang, 2016/06/28 05:01:46]

Done.

+        params.find(translate::kNumOfTranslationTriggerAlways);
+    if (it != params.end()) {
+      base::StringToInt(it->second,
+                        &num_of_translation_trigger_default_checked);
+    }
+  }
+
+  if (num_of_translation_trigger_default_checked < 0) {
+    return false;
+  }
+
+  // After N clicks on Translate for the same language.
+  // We check for == N instead of >= N because if the user translates with the
+  // "Always do this?" on, then the next time the bubble won't show up.
+  // The only chance the bubble will show up is after the user manually unchecks
+  // "Always do this?". In that case, since it is after user explictly unchecks,
+  // we should show as it as unchecked so we only check == N instead of >= N.
+  return GetTranslationAcceptedCount(language) ==
+         num_of_translation_trigger_default_checked;
+}
+
 // static
 void TranslatePrefs::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {