Update direct boot related documentation.

Also hide a few APIs as requested by council.  Add a method to
easily determine if a given File would already be encrypted at rest
by the OS.

Bug: 27531029
Change-Id: Icad5f1cd56411ad3ac707db85fd7449acdcc4b94
diff --git a/api/current.txt b/api/current.txt
index 889ed59..c82c04d 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -8019,8 +8019,6 @@
     method public abstract java.lang.String getPackageResourcePath();
     method public abstract android.content.res.Resources getResources();
     method public abstract android.content.SharedPreferences getSharedPreferences(java.lang.String, int);
-    method public abstract android.content.SharedPreferences getSharedPreferences(java.io.File, int);
-    method public abstract java.io.File getSharedPreferencesPath(java.lang.String);
     method public final java.lang.String getString(int);
     method public final java.lang.String getString(int, java.lang.Object...);
     method public abstract java.lang.Object getSystemService(java.lang.String);
@@ -29598,6 +29596,7 @@
     method public java.lang.String getMountedObbPath(java.lang.String);
     method public android.os.storage.StorageVolume getPrimaryVolume();
     method public android.os.storage.StorageVolume[] getVolumeList();
+    method public boolean isEncrypted(java.io.File);
     method public boolean isObbMounted(java.lang.String);
     method public boolean mountObb(java.lang.String, java.lang.String, android.os.storage.OnObbStateChangeListener);
     method public boolean unmountObb(java.lang.String, boolean, android.os.storage.OnObbStateChangeListener);
diff --git a/api/removed.txt b/api/removed.txt
index 9b5d3ab..36c8ce5 100644
--- a/api/removed.txt
+++ b/api/removed.txt
@@ -22,6 +22,8 @@
   public abstract class Context {
     method public deprecated android.content.Context createCredentialEncryptedStorageContext();
     method public deprecated android.content.Context createDeviceEncryptedStorageContext();
+    method public abstract android.content.SharedPreferences getSharedPreferences(java.io.File, int);
+    method public abstract java.io.File getSharedPreferencesPath(java.lang.String);
     method public deprecated boolean isCredentialEncryptedStorage();
     method public deprecated boolean isDeviceEncryptedStorage();
     method public deprecated boolean migrateDatabaseFrom(android.content.Context, java.lang.String);
diff --git a/api/system-current.txt b/api/system-current.txt
index ac59b39..24edfe0 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -8318,8 +8318,6 @@
     method public abstract java.lang.String getPackageResourcePath();
     method public abstract android.content.res.Resources getResources();
     method public abstract android.content.SharedPreferences getSharedPreferences(java.lang.String, int);
-    method public abstract android.content.SharedPreferences getSharedPreferences(java.io.File, int);
-    method public abstract java.io.File getSharedPreferencesPath(java.lang.String);
     method public final java.lang.String getString(int);
     method public final java.lang.String getString(int, java.lang.Object...);
     method public abstract java.lang.Object getSystemService(java.lang.String);
@@ -31910,6 +31908,7 @@
     method public java.lang.String getMountedObbPath(java.lang.String);
     method public android.os.storage.StorageVolume getPrimaryVolume();
     method public android.os.storage.StorageVolume[] getVolumeList();
+    method public boolean isEncrypted(java.io.File);
     method public boolean isObbMounted(java.lang.String);
     method public boolean mountObb(java.lang.String, java.lang.String, android.os.storage.OnObbStateChangeListener);
     method public boolean unmountObb(java.lang.String, boolean, android.os.storage.OnObbStateChangeListener);
diff --git a/api/system-removed.txt b/api/system-removed.txt
index 8bf59df..d48b9b3 100644
--- a/api/system-removed.txt
+++ b/api/system-removed.txt
@@ -20,6 +20,8 @@
   public abstract class Context {
     method public deprecated android.content.Context createCredentialEncryptedStorageContext();
     method public deprecated android.content.Context createDeviceEncryptedStorageContext();
+    method public abstract android.content.SharedPreferences getSharedPreferences(java.io.File, int);
+    method public abstract java.io.File getSharedPreferencesPath(java.lang.String);
     method public deprecated boolean isCredentialEncryptedStorage();
     method public deprecated boolean isDeviceEncryptedStorage();
     method public deprecated boolean migrateDatabaseFrom(android.content.Context, java.lang.String);
diff --git a/api/test-current.txt b/api/test-current.txt
index 908a50e..97e3b95 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -8024,8 +8024,6 @@
     method public abstract java.lang.String getPackageResourcePath();
     method public abstract android.content.res.Resources getResources();
     method public abstract android.content.SharedPreferences getSharedPreferences(java.lang.String, int);
-    method public abstract android.content.SharedPreferences getSharedPreferences(java.io.File, int);
-    method public abstract java.io.File getSharedPreferencesPath(java.lang.String);
     method public final java.lang.String getString(int);
     method public final java.lang.String getString(int, java.lang.Object...);
     method public abstract java.lang.Object getSystemService(java.lang.String);
@@ -29664,6 +29662,7 @@
     method public java.lang.String getMountedObbPath(java.lang.String);
     method public android.os.storage.StorageVolume getPrimaryVolume();
     method public android.os.storage.StorageVolume[] getVolumeList();
+    method public boolean isEncrypted(java.io.File);
     method public boolean isObbMounted(java.lang.String);
     method public boolean mountObb(java.lang.String, java.lang.String, android.os.storage.OnObbStateChangeListener);
     method public boolean unmountObb(java.lang.String, boolean, android.os.storage.OnObbStateChangeListener);
diff --git a/api/test-removed.txt b/api/test-removed.txt
index 9b5d3ab..36c8ce5 100644
--- a/api/test-removed.txt
+++ b/api/test-removed.txt
@@ -22,6 +22,8 @@
   public abstract class Context {
     method public deprecated android.content.Context createCredentialEncryptedStorageContext();
     method public deprecated android.content.Context createDeviceEncryptedStorageContext();
+    method public abstract android.content.SharedPreferences getSharedPreferences(java.io.File, int);
+    method public abstract java.io.File getSharedPreferencesPath(java.lang.String);
     method public deprecated boolean isCredentialEncryptedStorage();
     method public deprecated boolean isDeviceEncryptedStorage();
     method public deprecated boolean migrateDatabaseFrom(android.content.Context, java.lang.String);