Deactivate all input methods (except keyboard layouts) when screen is locked.

Reactivates them when screen is unlocked.

Note that if two or more keyboard layouts are active, you can switch layout by pressing the language hot-key (Shift+Alt), though the language indicator ("EN") is not clickable yet.

BUG=chromium-os:3936
BUG=chromium-os:2714
TEST=manual

Review URL: http://codereview.chromium.org/2771005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@49361 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 67 insertions, 0 deletions

diff --git a/chrome/browser/chromeos/login/screen_locker.cc b/chrome/browser/chromeos/login/screen_locker.cc
index 8d67d3b..abc569d 100644
--- a/chrome/browser/chromeos/login/screen_locker.cc
+++ b/chrome/browser/chromeos/login/screen_locker.cc
@@ -4,13 +4,19 @@
 
 #include "chrome/browser/chromeos/login/screen_locker.h"
 
+#include <string>
+#include <vector>
+
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
 #include "base/message_loop.h"
 #include "base/singleton.h"
+#include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_list.h"
+#include "chrome/browser/chromeos/cros/language_library.h"
 #include "chrome/browser/chromeos/cros/screen_lock_library.h"
+#include "chrome/browser/chromeos/language_preferences.h"
 #include "chrome/browser/chromeos/login/authenticator.h"
 #include "chrome/browser/chromeos/login/background_view.h"
 #include "chrome/browser/chromeos/login/login_utils.h"
@@ -32,6 +38,8 @@ namespace {
 // otherwise chromium process fails and the session is terminated.
 const int64 kRetryGrabIntervalMs = 500;
 const int kGrabFailureLimit = 60;
+// Each keyboard layout has a dummy input method ID which starts with "xkb:".
+const char kValidInputMethodPrefix[] = "xkb:";
 
 // Observer to start ScreenLocker when the screen lock
 class ScreenLockObserver : public chromeos::ScreenLockLibrary::Observer,
@@ -55,10 +63,12 @@ class ScreenLockObserver : public chromeos::ScreenLockLibrary::Observer,
   }
 
   virtual void LockScreen(chromeos::ScreenLockLibrary* obj) {
+    SetupInputMethodsForScreenLocker();
     chromeos::ScreenLocker::Show();
   }
 
   virtual void UnlockScreen(chromeos::ScreenLockLibrary* obj) {
+    RestoreInputMethods();
     chromeos::ScreenLocker::Hide();
   }
 
@@ -67,7 +77,64 @@ class ScreenLockObserver : public chromeos::ScreenLockLibrary::Observer,
   }
 
  private:
+  // Temporarily deactivates all input methods (e.g. Chinese, Japanese, Arabic)
+  // since they are not necessary to input a login password. Users are still
+  // able to use/switch active keyboard layouts (e.g. US qwerty, US dvorak,
+  // French).
+  void SetupInputMethodsForScreenLocker() {
+    if (chromeos::CrosLibrary::Get()->EnsureLoaded() &&
+        // The LockScreen function is also called when the OS is suspended, and
+        // in that case |saved_active_input_method_list_| might be non-empty.
+        saved_active_input_method_list_.empty()) {
+      chromeos::LanguageLibrary* language =
+          chromeos::CrosLibrary::Get()->GetLanguageLibrary();
+      saved_current_input_method_id_ = language->current_input_method().id;
+      // TODO(yusukes): save/restore previous input method ID.
+      scoped_ptr<chromeos::InputMethodDescriptors> active_input_method_list(
+          language->GetActiveInputMethods());
+
+      chromeos::ImeConfigValue value;
+      value.type = chromeos::ImeConfigValue::kValueTypeStringList;
+      for (size_t i = 0; i < active_input_method_list->size(); ++i) {
+        const std::string& input_method_id = active_input_method_list->at(i).id;
+        saved_active_input_method_list_.push_back(input_method_id);
+        // |active_input_method_list| contains both input method descriptions
+        // and keyboard layout descriptions.
+        if (!StartsWithASCII(input_method_id, kValidInputMethodPrefix, true))
+          continue;
+        value.string_list_value.push_back(input_method_id);
+      }
+      if (value.string_list_value.empty()) {
+        value.string_list_value.push_back(kFallbackInputMethodId);  // US qwerty
+      }
+      language->SetImeConfig(chromeos::kGeneralSectionName,
+                             chromeos::kPreloadEnginesConfigName,
+                             value);
+    }
+  }
+
+  void RestoreInputMethods() {
+    if (chromeos::CrosLibrary::Get()->EnsureLoaded() &&
+        !saved_active_input_method_list_.empty()) {
+      chromeos::LanguageLibrary* language =
+          chromeos::CrosLibrary::Get()->GetLanguageLibrary();
+
+      chromeos::ImeConfigValue value;
+      value.type = chromeos::ImeConfigValue::kValueTypeStringList;
+      value.string_list_value = saved_active_input_method_list_;
+      language->SetImeConfig(chromeos::kGeneralSectionName,
+                             chromeos::kPreloadEnginesConfigName,
+                             value);
+      language->ChangeInputMethod(saved_current_input_method_id_);
+
+      saved_current_input_method_id_.clear();
+      saved_active_input_method_list_.clear();
+    }
+  }
+
   NotificationRegistrar registrar_;
+  std::string saved_current_input_method_id_;
+  std::vector<std::string> saved_active_input_method_list_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenLockObserver);
 };