Move passphrase dialog logic to the enum.

In preparation for a bug fix.

BUG=419927

Review URL: https://codereview.chromium.org/642623002

Cr-Commit-Position: refs/heads/master@{#298900}

sync/android/java/src/org/chromium/sync/internal_api/pub/SyncDecryptionPassphraseType.java

@@ -7,6 +7,9 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 
+import java.util.HashSet;
+import java.util.Set;
+
 /**
  * This enum describes the type of passphrase required, if any, to decrypt synced data.
  *
@@ -51,6 +54,50 @@ private SyncDecryptionPassphraseType(int nativeValue) {
         mNativeValue = nativeValue;
     }
 
+
+    public Set<SyncDecryptionPassphraseType> getVisibleTypes() {
+        Set<SyncDecryptionPassphraseType> visibleTypes = new HashSet<>();
+        switch (this) {
+            case NONE:  // Intentional fall through.
+            case IMPLICIT_PASSPHRASE:  // Intentional fall through.
+            case KEYSTORE_PASSPHRASE:
+                visibleTypes.add(this);
+                visibleTypes.add(CUSTOM_PASSPHRASE);
+                break;
+            case FROZEN_IMPLICIT_PASSPHRASE:
+                visibleTypes.add(KEYSTORE_PASSPHRASE);
+                visibleTypes.add(FROZEN_IMPLICIT_PASSPHRASE);
+                break;
+            case CUSTOM_PASSPHRASE:
+                visibleTypes.add(KEYSTORE_PASSPHRASE);
+                visibleTypes.add(CUSTOM_PASSPHRASE);
+                break;
+            case INVALID:  // Intentional fall through.
+            default:
+                visibleTypes.add(this);
+                break;
+        }
+        return visibleTypes;
+    }
+
+    public Set<SyncDecryptionPassphraseType> getAllowedTypes() {
+        Set<SyncDecryptionPassphraseType> allowedTypes = new HashSet<>();
+        switch (this) {
+            case NONE:  // Intentional fall through.
+            case IMPLICIT_PASSPHRASE:  // Intentional fall through.
+            case KEYSTORE_PASSPHRASE:
+                allowedTypes.add(this);
+                allowedTypes.add(CUSTOM_PASSPHRASE);
+                break;
+            case FROZEN_IMPLICIT_PASSPHRASE:  // Intentional fall through.
+            case CUSTOM_PASSPHRASE:  // Intentional fall through.
+            case INVALID:  // Intentional fall through.
+            default:
+                break;
+        }
+        return allowedTypes;
+    }
+
     public int internalValue() {
         // Since the values in this enums are constant and very small, this cast is safe.
         return mNativeValue;