Add support to BitmapFactory for decoding a bitmap from a MemoryFile FileDescriptor.

graphics/java/android/graphics/BitmapFactory.java

@@ -18,6 +18,7 @@ package android.graphics;
 
 import android.content.res.AssetManager;
 import android.content.res.Resources;
+import android.os.MemoryFile;
 import android.util.DisplayMetrics;
 import android.util.TypedValue;
 
@@ -435,6 +436,17 @@ public class BitmapFactory {
      * @return the decoded bitmap, or null
      */
     public static Bitmap decodeFileDescriptor(FileDescriptor fd, Rect outPadding, Options opts) {
+        try {
+            if (MemoryFile.isMemoryFile(fd)) {
+                int mappedlength = MemoryFile.getMappedSize(fd);
+                MemoryFile file = new MemoryFile(fd, mappedlength, "r");
+                InputStream is = file.getInputStream();
+                return decodeStream(is, outPadding, opts);
+            }
+        } catch (IOException ex) {
+            // invalid filedescriptor, no need to call nativeDecodeFileDescriptor()
+            return null;
+        }
         return nativeDecodeFileDescriptor(fd, outPadding, opts);
     }
 
@@ -447,7 +459,7 @@ public class BitmapFactory {
      * @return the decoded bitmap, or null
      */
     public static Bitmap decodeFileDescriptor(FileDescriptor fd) {
-        return nativeDecodeFileDescriptor(fd, null, null);
+        return decodeFileDescriptor(fd, null, null);
     }
 
     private static native Bitmap nativeDecodeStream(InputStream is, byte[] storage,