Add finalizers to Web Payment Java objects that own native objects

These C++ objects are destroyed in PaymentRequestImpl.closeUIAndDestroyNativeObjects().
However, if an object is garbage-collected for any reason without
PaymentRequestImpl.closeUIAndDestroyNativeObjects() being called,
then it will cause a memory leak.

A finalize method should be added to these objects to ensure destruction
of the owned C++ objects.

Bug: 1090918
Change-Id: I12df86f9705d81d630b63223d15354d2b022e888
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2392290
Commit-Queue: DongJun Kim <djmix.kim@samsung.com>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804820}

components/payments/content/android/java/src/org/chromium/components/payments/CurrencyFormatter.java

@@ -46,6 +46,16 @@ public class CurrencyFormatter {
         }
     }
 
+    /**
+     * Destroys native object if owned object is not destroyed.
+     *
+     * @see java.lang.Object#finalize()
+     */
+    @Override
+    public void finalize() throws Throwable {
+        destroy();
+    }
+
     /** @return The currency code formatted for display. */
     public String getFormattedCurrencyCode() {
         return CurrencyFormatterJni.get().getFormattedCurrencyCode(

components/payments/content/android/java/src/org/chromium/components/payments/JourneyLogger.java

@@ -35,6 +35,16 @@ public class JourneyLogger {
         }
     }
 
+    /**
+     * Destroys native object if owned object is not destroyed.
+     *
+     * @see java.lang.Object#finalize()
+     */
+    @Override
+    public void finalize() throws Throwable {
+        destroy();
+    }
+
     /**
      * Sets the number of suggestions shown for the specified section.
      *

components/payments/content/android/java/src/org/chromium/components/payments/PaymentDetailsUpdateServiceHelper.java

@@ -153,7 +153,17 @@ public class PaymentDetailsUpdateServiceHelper {
      */
     public void reset() {
         ThreadUtils.assertOnUiThread();
-        sInstance = null;
+        if (sInstance != null) sInstance = null;
+    }
+
+    /**
+     * Resets singleton instance if it is not destroyed.
+     *
+     * @see java.lang.Object#finalize()
+     */
+    @Override
+    public void finalize() throws Throwable {
+        reset();
     }
 
     /**

components/payments/content/android/java/src/org/chromium/components/payments/PaymentHandlerHost.java

@@ -73,8 +73,20 @@ public class PaymentHandlerHost {
 
     /** Destroys the native bridge. This object shouldn't be used afterwards. */
     public void destroy() {
-        PaymentHandlerHostJni.get().destroy(mNativePointer);
-        mNativePointer = 0;
+        if (mNativePointer != 0) {
+            PaymentHandlerHostJni.get().destroy(mNativePointer);
+            mNativePointer = 0;
+        }
+    }
+
+    /**
+     * Destroys native object if owned object is not destroyed.
+     *
+     * @see java.lang.Object#finalize()
+     */
+    @Override
+    public void finalize() throws Throwable {
+        destroy();
     }
 
     /**

components/payments/content/android/java/src/org/chromium/components/payments/PaymentRequestSpec.java

@@ -80,6 +80,16 @@ public class PaymentRequestSpec {
         mNativePointer = 0;
     }
 
+    /**
+     * Destroys native object if owned object is not destroyed.
+     *
+     * @see java.lang.Object#finalize()
+     */
+    @Override
+    public void finalize() throws Throwable {
+        destroy();
+    }
+
     @CalledByNative
     private long getNativePointer() {
         return mNativePointer;