Remove support for converting from FDE to FBE

Devices that launched with Android 10 or later require FBE (File Based
Encryption) from the beginning, so there's no need to support converting
to FBE after the fact anymore.  This was only ever a developer option,
so it probably wasn't used much.  And in any case, it's not used
anymore, as isConvertibleToFBE() is hard-coded to return false.  Besides
the fact that FBE has been required for several releases now, this
functionality was only ever available on devices that use FDE (Full Disk
Encryption), but FDE support has been removed from Android.

Therefore, remove this unused code.

Bug: 208476087
Change-Id: I1f56c8e05fb3fba09aab4bf5f8609b0f552b8999

4 files changed, 4 insertions, 37 deletions

diff --git a/core/java/android/os/storage/IStorageManager.aidl b/core/java/android/os/storage/IStorageManager.aidl
index 5bf1b04b8e53..ef33543ba7ad 100644
--- a/core/java/android/os/storage/IStorageManager.aidl
+++ b/core/java/android/os/storage/IStorageManager.aidl
@@ -125,7 +125,6 @@ interface IStorageManager {
     boolean isUserKeyUnlocked(int userId) = 65;
     void prepareUserStorage(in String volumeUuid, int userId, int serialNumber, int flags) = 66;
     void destroyUserStorage(in String volumeUuid, int userId, int flags) = 67;
-    boolean isConvertibleToFBE() = 68;
     void addUserKeyAuth(int userId, int serialNumber, in byte[] secret) = 70;
     void fixateNewestUserKeyAuth(int userId) = 71;
     void fstrim(int flags, IVoldTaskListener listener) = 72;
diff --git a/packages/SettingsLib/res/values/strings.xml b/packages/SettingsLib/res/values/strings.xml
index a56c49088b67..534e41c42467 100644
--- a/packages/SettingsLib/res/values/strings.xml
+++ b/packages/SettingsLib/res/values/strings.xml
@@ -1038,23 +1038,6 @@
     <!-- Developer settings: text for the WebView provider selection toast shown if an invalid provider was chosen (i.e. the setting list was stale). [CHAR LIMIT=NONE] -->
     <string name="select_webview_provider_toast_text">This choice is no longer valid. Try again.</string>
 
-    <!-- Developer settings screen, convert userdata to file encryption option name -->
-    <string name="convert_to_file_encryption">Convert to file encryption</string>
-    <!-- Developer settings screen, convert userdata to file encryption summary when option is available -->
-    <string name="convert_to_file_encryption_enabled">Convert\u2026</string>
-    <!-- Developer settings screen, convert userdata to file encryption summary when option is already done -->
-    <string name="convert_to_file_encryption_done">Already file encrypted</string>
-    <!-- Title used on dialog with final prompt for converting to file encryption -->
-    <string name="title_convert_fbe">Converting to file based encryption</string>
-    <!-- Warning displayed on dialog with final prompt for converting to file encryption -->
-    <string name="convert_to_fbe_warning">
-        Convert data partition to file based encryption.\n
-        !!Warning!! This will erase all your data.\n
-        This feature is alpha, and may not work correctly.\n
-        Press \'Wipe and convert\u2026\' to continue.</string>
-    <!-- Button on dialog that triggers convertion to file encryption -->
-    <string name="button_convert_fbe">Wipe and convert\u2026</string>
-
     <!-- Name of feature to change color setting for the display [CHAR LIMIT=60] -->
     <string name="picture_color_mode">Picture color mode</string>
 
diff --git a/proto/src/metrics_constants/metrics_constants.proto b/proto/src/metrics_constants/metrics_constants.proto
index 3f712dd1492f..3801c2473c11 100644
--- a/proto/src/metrics_constants/metrics_constants.proto
+++ b/proto/src/metrics_constants/metrics_constants.proto
@@ -2260,10 +2260,12 @@ message MetricsEvent {
     ACCOUNTS_WORK_PROFILE_SETTINGS = 401;
 
     // Settings -> Dev options -> Convert to file encryption
-    CONVERT_FBE = 402;
+    // DEPRECATED: this setting was removed in Android T.
+    CONVERT_FBE = 402 [deprecated=true];
 
     // Settings -> Dev options -> Convert to file encryption -> WIPE AND CONVERT...
-    CONVERT_FBE_CONFIRM = 403;
+    // DEPRECATED: this setting was removed in Android T.
+    CONVERT_FBE_CONFIRM = 403 [deprecated=true];
 
     // Settings -> Dev options -> Running services
     RUNNING_SERVICES = 404;
diff --git a/services/core/java/com/android/server/StorageManagerService.java b/services/core/java/com/android/server/StorageManagerService.java
index 9c8cb8c5267d..9f32888262ee 100644
--- a/services/core/java/com/android/server/StorageManagerService.java
+++ b/services/core/java/com/android/server/StorageManagerService.java
@@ -3072,23 +3072,6 @@ class StorageManagerService extends IStorageManager.Stub
     }
 
     /**
-     * Is userdata convertible to file based encryption?
-     * @return non zero for convertible
-     */
-    @Override
-    public boolean isConvertibleToFBE() throws RemoteException {
-        mContext.enforceCallingOrSelfPermission(Manifest.permission.CRYPT_KEEPER,
-            "no permission to access the crypt keeper");
-
-        try {
-            return mVold.isConvertibleToFbe();
-        } catch (Exception e) {
-            Slog.wtf(TAG, e);
-            return false;
-        }
-    }
-
-    /**
      * Check whether the device supports filesystem checkpointing.
      *
      * @return true if the device supports filesystem checkpointing, false otherwise.