Do not disable ARC IMEs when they are still in the prefs

BUG=879365,845079
TEST=Sign in, enter tablet mode, install gboard, enable gboard,
 use it, enter laptop mode, enter tablet mode again, use gboard,
 confirm the IME confirmation dialog is not shown.

Change-Id: I8eb9ca17433f79fd76e7c471bb6c7929cad68150
Reviewed-on: https://chromium-review.googlesource.com/1199501Reviewed-by: Yuichiro Hanada <yhanada@chromium.org>
Commit-Queue: Yusuke Sato <yusukes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588419}

chrome/browser/chromeos/arc/input_method_manager/arc_input_method_manager_service.cc

@@ -301,6 +301,19 @@ void ArcInputMethodManagerService::ImeMenuListChanged() {
         return chromeos::extension_ime_util::IsArcIME(id);
       });
 
+  // TODO(yhanada|yusukes): Instead of observing ImeMenuListChanged(), it's
+  // probably better to just observe the pref (and not disabling ones still
+  // in the prefs.) See also the comment below in the second for-loop.
+  std::set<std::string> active_ime_ids_on_prefs;
+  {
+    const std::string active_ime_ids =
+        profile_->GetPrefs()->GetString(prefs::kLanguageEnabledImes);
+    std::vector<base::StringPiece> active_ime_list = base::SplitStringPiece(
+        active_ime_ids, ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+    for (const auto& id : active_ime_list)
+      active_ime_ids_on_prefs.insert(id.as_string());
+  }
+
   for (const auto& id : new_arc_active_ime_ids) {
     // Enable the IME which is not currently enabled.
     if (!active_arc_ime_ids_.count(id))
@@ -308,9 +321,22 @@ void ArcInputMethodManagerService::ImeMenuListChanged() {
   }
 
   for (const auto& id : active_arc_ime_ids_) {
-    // Disable the IME which is currently enabled.
-    if (!new_arc_active_ime_ids.count(id))
+    if (!new_arc_active_ime_ids.count(id) &&
+        !active_ime_ids_on_prefs.count(id)) {
+      // This path is taken in the following two cases:
+      // 1) The device is in tablet mode, and the user disabled the IME via
+      //    chrome://settings.
+      // 2) The device was just switched to laptop mode, and this service
+      //    disallowed Android IMEs.
+      // In the former case, |active_ime_ids_on_prefs| doesn't have the IME,
+      // but in the latter case, the set still has it. Here, disable the IME
+      // only for the former case so that the temporary deactivation of the
+      // IME on laptop mode wouldn't be propagated to the container. Otherwise,
+      // the IME confirmation dialog will be shown again next time when you
+      // use the IME in tablet mode.
+      // TODO(yhanada|yusukes): Only observe the prefs and remove the hack.
       EnableIme(id, false /* enable */);
+    }
   }
   active_arc_ime_ids_.swap(new_arc_active_ime_ids);
 }

chrome/browser/chromeos/arc/input_method_manager/arc_input_method_manager_service_unittest.cc

@@ -273,12 +273,49 @@ TEST_F(ArcInputMethodManagerServiceTest, EnableIme) {
             std::get<std::string>(bridge()->enable_ime_calls_[1]));
   EXPECT_FALSE(std::get<bool>(bridge()->enable_ime_calls_[1]));
 
-  // EnableIme is not called when non ARC IME is disable.
+  // EnableIme is not called when non ARC IME is disabled.
   imm()->state()->RemoveActiveInputMethodId(extension_ime_id);
   service()->ImeMenuListChanged();
   EXPECT_EQ(2u, bridge()->enable_ime_calls_.size());
 }
 
+TEST_F(ArcInputMethodManagerServiceTest, EnableIme_WithPrefs) {
+  namespace ceiu = chromeos::extension_ime_util;
+  using crx_file::id_util::GenerateId;
+
+  base::test::ScopedFeatureList feature;
+  feature.InitAndEnableFeature(kEnableInputMethodFeature);
+  ToggleTabletMode(true);
+
+  ASSERT_EQ(0u, bridge()->enable_ime_calls_.size());
+
+  const std::string component_extension_ime_id =
+      ceiu::GetComponentInputMethodID(
+          GenerateId("test.component.extension.ime"), "us");
+  const std::string arc_ime_id =
+      ceiu::GetArcInputMethodID(GenerateId("test.arc.ime"), "us");
+
+  imm()->state()->AddActiveInputMethodId(component_extension_ime_id);
+  service()->ImeMenuListChanged();
+  EXPECT_EQ(0u, bridge()->enable_ime_calls_.size());
+
+  imm()->state()->AddActiveInputMethodId(arc_ime_id);
+  service()->ImeMenuListChanged();
+  ASSERT_EQ(1u, bridge()->enable_ime_calls_.size());
+
+  // Test the case where |arc_ime_id| is temporarily disallowed because of the
+  // toggling to the laptop mode. In that case, the prefs still have the IME's
+  // ID.
+  profile()->GetPrefs()->SetString(
+      prefs::kLanguageEnabledImes,
+      base::StringPrintf("%s,%s", component_extension_ime_id.c_str(),
+                         arc_ime_id.c_str()));
+  imm()->state()->RemoveActiveInputMethodId(arc_ime_id);
+  service()->ImeMenuListChanged();
+  // Verify that EnableIme(id, false) is NOT called.
+  EXPECT_EQ(1u, bridge()->enable_ime_calls_.size());  // still 1u, not 2u.
+}
+
 TEST_F(ArcInputMethodManagerServiceTest, SwitchImeTo) {
   namespace ceiu = chromeos::extension_ime_util;
   using crx_file::id_util::GenerateId;