tdf#124042: Add SAL_INFOs for iOS about the CGContext life cycle in LOKit

Use the same logging tag as in vcl for uniformity. Helps in tracing
the life cycle and usage of CGContexts.

Change-Id: I89c33ac63fa26e10a8866c2aacecce89ef9b5f6b

desktop/source/lib/init.cxx

@@ -2349,11 +2349,15 @@ static void doc_paintTile(LibreOfficeKitDocument* pThis,
 #if defined(IOS)
     CGContextRef cgc = CGBitmapContextCreate(pBuffer, nCanvasWidth, nCanvasHeight, 8, nCanvasWidth*4, CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipFirst | kCGImageByteOrder32Little);
 
+    // Use the vcl.cg tag even if this code is not in vcl, to match all other SAL_INFO logging about Core Graphics, in vcl.
+    SAL_INFO( "vcl.cg", "CGBitmapContextCreate(" << nCanvasWidth << "x" << nCanvasHeight << "x32) = " << cgc );
+
     CGContextTranslateCTM(cgc, 0, nCanvasHeight);
     CGContextScaleCTM(cgc, fDPIScaleX, -fDPIScaleX);
 
     doc_paintTileToCGContext(pThis, (void*) cgc, nCanvasWidth, nCanvasHeight, nTilePosX, nTilePosY, nTileWidth, nTileHeight);
 
+    SAL_INFO( "vcl.cg", "CGContextRelease(" << cgc << ")" );
     CGContextRelease(cgc);
 
 #else
@@ -3891,6 +3895,8 @@ static void doc_paintWindowDPI(LibreOfficeKitDocument* /*pThis*/, unsigned nLOKW
 
     CGContextRef cgc = CGBitmapContextCreate(pBuffer, nWidth, nHeight, 8, nWidth*4, CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipFirst | kCGImageByteOrder32Little);
 
+    SAL_INFO( "vcl.cg", "CGBitmapContextCreate(" << nWidth << "x" << nHeight << "x32) = " << cgc);
+
     CGContextTranslateCTM(cgc, 0, nHeight);
     CGContextScaleCTM(cgc, fDPIScale, -fDPIScale);
 
@@ -3910,6 +3916,7 @@ static void doc_paintWindowDPI(LibreOfficeKitDocument* /*pThis*/, unsigned nLOKW
     pWindow->PaintToDevice(pDevice.get(), Point(0, 0), Size());
     comphelper::LibreOfficeKit::setDialogPainting(false);
 
+    SAL_INFO( "vcl.cg", "CGContextRelease(" << cgc << ")" );
     CGContextRelease(cgc);
 
 #else