Retain the gainmap during Bitmap.asShared()

This was getting lost in some IPCs because the gainmap of an Ashmem
Bitmap was passed through as a local native pointer instead of also
being an Ashmem object.

Test: GainmapTests
Test: GainmapTest
Test: BitmapTest
Bug: 390675155
Flag: EXEMPT bugfix
Change-Id: I1940c5eb58d1cc5a83836f77e2618bd86ca35741

2 files changed, 18 insertions, 2 deletions

diff --git a/graphics/java/android/graphics/Bitmap.java b/graphics/java/android/graphics/Bitmap.java
index cd5a54c2fd3f..a4ba2b398deb 100644
--- a/graphics/java/android/graphics/Bitmap.java
+++ b/graphics/java/android/graphics/Bitmap.java
@@ -755,6 +755,9 @@ public final class Bitmap implements Parcelable {
         if (b != null) {
             b.setPremultiplied(mRequestPremultiplied);
             b.mDensity = mDensity;
+            if (hasGainmap()) {
+                b.setGainmap(getGainmap().asShared());
+            }
         }
         return b;
     }
@@ -767,7 +770,8 @@ public final class Bitmap implements Parcelable {
      */
     @NonNull
     public Bitmap asShared() {
-        if (nativeIsBackedByAshmem(mNativePtr) && nativeIsImmutable(mNativePtr)) {
+        if (nativeIsBackedByAshmem(mNativePtr) && nativeIsImmutable(mNativePtr)
+                && (!hasGainmap() || getGainmap().asShared() == getGainmap())) {
             return this;
         }
         Bitmap shared = createAshmemBitmap();
@@ -2091,7 +2095,7 @@ public final class Bitmap implements Parcelable {
      */
     public void setGainmap(@Nullable Gainmap gainmap) {
         checkRecycled("Bitmap is recycled");
-        mGainmap = null;
+        mGainmap = gainmap;
         nativeSetGainmap(mNativePtr, gainmap == null ? 0 : gainmap.mNativePtr);
     }
 
diff --git a/graphics/java/android/graphics/Gainmap.java b/graphics/java/android/graphics/Gainmap.java
index 7fc13db85659..2417a1270bc5 100644
--- a/graphics/java/android/graphics/Gainmap.java
+++ b/graphics/java/android/graphics/Gainmap.java
@@ -161,6 +161,18 @@ public final class Gainmap implements Parcelable {
     }
 
     /**
+     * @hide
+     */
+    public Gainmap asShared() {
+        final Bitmap sharedContents = mGainmapContents.asShared();
+        if (sharedContents == mGainmapContents) {
+            return this;
+        } else {
+            return new Gainmap(sharedContents, nCreateCopy(mNativePtr));
+        }
+    }
+
+    /**
      * @return Returns the image data of the gainmap represented as a Bitmap. This is represented
      * as a Bitmap for broad API compatibility, however certain aspects of the Bitmap are ignored
      * such as {@link Bitmap#getColorSpace()} or {@link Bitmap#getGainmap()} as they are not