[Translate Manual Trigger] Fixing IPH triggering.

Fixing logic bug in IPH triggering logic. Adding a variation for "force trigger on english" experiment as a flag to automatically trigger it.

Bug: 883456
Change-Id: Ice024580601fdfe5debb862bb7cfeff956b04dbc
Reviewed-on: https://chromium-review.googlesource.com/c/1318631Reviewed-by: anthonyvd <anthonyvd@chromium.org>
Commit-Queue: Alexandre Frechette <frechette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605757}

chrome/browser/about_flags.cc

@@ -1187,6 +1187,10 @@ const FeatureEntry::FeatureParam kTranslateForceTriggerOnEnglishHeuristic[] = {
 const FeatureEntry::FeatureParam kTranslateForceTriggerOnEnglishGeo[] = {
     {language::kOverrideModelKey, language::kOverrideModelGeoValue},
     {language::kEnforceRankerKey, "false"}};
+const FeatureEntry::FeatureParam kTranslateForceTriggerOnEnglishBackoff[] = {
+    {language::kOverrideModelKey, language::kOverrideModelDefaultValue},
+    {language::kEnforceRankerKey, "false"},
+    {language::kBackoffThresholdKey, "0"}};
 const FeatureEntry::FeatureVariation
     kTranslateForceTriggerOnEnglishVariations[] = {
         {"(Heuristic model without Ranker)",
@@ -1194,7 +1198,8 @@ const FeatureEntry::FeatureVariation
          arraysize(kTranslateForceTriggerOnEnglishHeuristic), nullptr},
         {"(Geo model without Ranker)", kTranslateForceTriggerOnEnglishGeo,
          arraysize(kTranslateForceTriggerOnEnglishGeo), nullptr},
-};
+        {"(Zero threshold)", kTranslateForceTriggerOnEnglishBackoff,
+         arraysize(kTranslateForceTriggerOnEnglishBackoff), nullptr}};
 #endif  // defined(OS_ANDROID)
 
 #if !defined(OS_ANDROID)

chrome/browser/translate/android/translate_bridge.cc

@@ -58,7 +58,7 @@ static jboolean JNI_TranslateBridge_ShouldShowManualTranslateIPH(
 
   return base::StartsWith(page_lang, "en",
                           base::CompareCase::INSENSITIVE_ASCII) &&
-         language::ShouldForceTriggerTranslateOnEnglishPages(
+         !language::ShouldForceTriggerTranslateOnEnglishPages(
              translate_prefs->GetForceTriggerOnEnglishPagesCount()) &&
-         manager->GetLanguageState().translate_enabled();
+         !manager->GetLanguageState().translate_enabled();
 }

components/language/core/common/language_experiments.cc

@@ -26,6 +26,7 @@ const char kOverrideModelKey[] = "override_model";
 const char kEnforceRankerKey[] = "enforce_ranker";
 const char kOverrideModelHeuristicValue[] = "heuristic";
 const char kOverrideModelGeoValue[] = "geo";
+const char kOverrideModelDefaultValue[] = "default";
 
 OverrideLanguageModel GetOverrideLanguageModel() {
   std::map<std::string, std::string> params;

components/language/core/common/language_experiments.h

@@ -27,6 +27,8 @@ extern const char kOverrideModelKey[];
 extern const char kEnforceRankerKey[];
 extern const char kOverrideModelHeuristicValue[];
 extern const char kOverrideModelGeoValue[];
+extern const char kOverrideModelDefaultValue[];
+extern const char kBackoffThresholdKey[];
 
 enum class OverrideLanguageModel {
   DEFAULT,