Fix redundant synchronized/GuardedBy

 SafeCloseImageReaderProxy#wrapImageProxy() is private and annotated
 @GuardedBy("mLock") and all access already occurs within a synchronized
 block, so the internal synchronized block can be removed.

 SafeCloseImageReaderProxy#safeClose() is used externally, and
 internally contains a synchronized block, so it does not need to be
 annotated @GuardedBy("mLock")

 Private member variables SafeCloseImageReaderProxy#mOutstandingImages
 and SafeCloseImageReaderProxy#mIsClosed do not need to be volatile
 since they are only written/read when the same monitor lock is held.

Test: ./gradlew camera:camera-core:connectedCheck
Change-Id: I8baec99202f0e228aec03f3ac051cbefb72e4c3b

Author: temcguir

camera/camera-core/src/main/java/androidx/camera/core/SafeCloseImageReaderProxy.java

@@ -34,9 +34,9 @@ class SafeCloseImageReaderProxy implements ImageReaderProxy {
     private final Object mLock = new Object();
 
     @GuardedBy("mLock")
-    private volatile int mOutstandingImages = 0;
+    private int mOutstandingImages = 0;
     @GuardedBy("mLock")
-    private volatile boolean mIsClosed = false;
+    private boolean mIsClosed = false;
 
     // The wrapped instance of ImageReaderProxy
     @GuardedBy("mLock")
@@ -46,7 +46,7 @@ class SafeCloseImageReaderProxy implements ImageReaderProxy {
     private final Surface mSurface;
 
     // Called after images are closed to check if the ImageReaderProxy should be closed
-    private ForwardingImageProxy.OnImageCloseListener mImageCloseListener = (image) -> {
+    private final ForwardingImageProxy.OnImageCloseListener mImageCloseListener = (image) -> {
         synchronized (mLock) {
             mOutstandingImages--;
             if (mIsClosed && mOutstandingImages == 0) {
@@ -97,16 +97,14 @@ public void close() {
     @GuardedBy("mLock")
     @Nullable
     private ImageProxy wrapImageProxy(@Nullable ImageProxy imageProxy) {
-        synchronized (mLock) {
-            if (imageProxy != null) {
-                mOutstandingImages++;
-                SingleCloseImageProxy singleCloseImageProxy =
-                        new SingleCloseImageProxy(imageProxy);
-                singleCloseImageProxy.addOnImageCloseListener(mImageCloseListener);
-                return singleCloseImageProxy;
-            } else {
-                return null;
-            }
+        if (imageProxy != null) {
+            mOutstandingImages++;
+            SingleCloseImageProxy singleCloseImageProxy =
+                    new SingleCloseImageProxy(imageProxy);
+            singleCloseImageProxy.addOnImageCloseListener(mImageCloseListener);
+            return singleCloseImageProxy;
+        } else {
+            return null;
         }
     }
 
@@ -117,7 +115,6 @@ private ImageProxy wrapImageProxy(@Nullable ImageProxy imageProxy) {
      * <p>Once this has been called, no more additional ImageProxy can be acquired from the
      * {@link SafeCloseImageReaderProxy}.
      */
-    @GuardedBy("mLock")
     void safeClose() {
         synchronized (mLock) {
             mIsClosed = true;