Set flagForceAscii for device password entries

Since the beginning [1], ChooseLockPassword#validatePassword() has never
accepted non-ASCII characters [2].  Hence we can safely specify
EditorInfo#IME_FLAG_FORCE_ASCII so that IMEs can optimize their UX based
on this flag.  Note that EditorInfo#IME_FLAG_FORCE_ASCII is just a hint
for the IME so there should be no behavior change in the system side.

Note also that EditorInfo#IME_FLAG_FORCE_ASCII has been used in KeyGuard
(keyguard_password_view.xml) since JB MR-1 [3] so this flag is considered
to be well tested.

 [1]: 00d2476d8f
 [2]: Only character c where 32 <= c <= 126 is accepted
 [3]: Id75286113771ca1407e9db182172b580f870b612

Test: Run `adb shell dumpsys input_method` when the password entry
      field is focused to make sure that 'imeOptions' parameter
      has 0x80000000 bit. Tested the following scenarios:
       - PIN on a direct-boot disabled device
       - PIN on a direct-boot enabled device
       - Password on a direct-boot disabled device
       - Password on a direct-boot enabled device
Fixes: 27858858
Change-Id: I3075e24c6dac4d49f4d0e56a0d4d8434a323754d

res/layout-land/confirm_lock_password.xml

@@ -74,7 +74,7 @@
                 android:layout_gravity="center_horizontal|bottom"
                 android:layout_marginBottom="26dp"
                 android:inputType="textPassword"
-                android:imeOptions="actionNext|flagNoFullscreen"
+                android:imeOptions="actionNext|flagNoFullscreen|flagForceAscii"
                 android:gravity="center"
                 android:textSize="16sp"
                 style="@style/TextAppearance.PasswordEntry"/>

res/layout/choose_lock_password.xml

@@ -48,7 +48,7 @@
             android:layout_gravity="center"
             android:gravity="center"
             android:inputType="textPassword"
-            android:imeOptions="actionNext|flagNoExtractUi"
+            android:imeOptions="actionNext|flagNoExtractUi|flagForceAscii"
             android:textSize="24sp"
             style="@style/TextAppearance.PasswordEntry"/>
 

res/layout/confirm_lock_password_base.xml

@@ -70,7 +70,7 @@
             android:layout_gravity="center_horizontal"
             android:layout_marginTop="-40dp"
             android:inputType="textPassword"
-            android:imeOptions="actionNext|flagNoFullscreen"
+            android:imeOptions="actionNext|flagNoFullscreen|flagForceAscii"
             android:gravity="center"
             android:textSize="16sp"
             style="@style/TextAppearance.PasswordEntry"/>

res/layout/confirm_lock_password_internal.xml

@@ -67,7 +67,7 @@
             android:layout_gravity="center_horizontal"
             android:layout_marginTop="-40dp"
             android:inputType="textPassword"
-            android:imeOptions="actionNext|flagNoFullscreen"
+            android:imeOptions="actionNext|flagNoFullscreen|flagForceAscii"
             android:gravity="center"
             android:textSize="16sp"
             style="@style/TextAppearance.PasswordEntry"/>

res/layout/crypt_keeper_password_field.xml

@@ -27,6 +27,7 @@
         android:layout_width="0dip"
         android:layout_weight="1"
         android:inputType="textPassword"
+        android:imeOptions="flagForceAscii"
         android:textSize="16sp"
         android:padding="10sp"
         android:maxLength="500"