EngCreateBitmap may return null. Add return value checks

svn path=/trunk/; revision=21589

reactos/subsystems/win32/win32k/eng/engmisc.c

@@ -68,6 +68,13 @@ IntEngEnter(PINTENG_ENTER_LEAVE EnterLeave,
     EnterLeave->OutputBitmap = EngCreateBitmap(BitmapSize, Width,
                                                DestObj->iBitmapFormat,
                                                BMF_TOPDOWN | BMF_NOZEROINIT, NULL);
+                                               
+    if (!EnterLeave->OutputBitmap)
+      {
+      DPRINT1("EngCreateBitmap() failed\n");
+      return FALSE;
+      }
+      
     *OutputObj = EngLockSurface((HSURF)EnterLeave->OutputBitmap);
 
     EnterLeave->DestRect.left = 0;

reactos/subsystems/win32/win32k/eng/surface.c

@@ -122,6 +122,12 @@ EngCreateDeviceBitmap(IN DHSURF dhsurf,
   SURFOBJ *SurfObj;
 
   NewBitmap = EngCreateBitmap(Size, DIB_GetDIBWidthBytes(Size.cx, BitsPerFormat(Format)), Format, 0, NULL);
+  if(!NewBitmap) 
+  {
+    DPRINT1("EngCreateBitmap failed\n");
+    return 0;
+  }
+    
   SurfObj = EngLockSurface((HSURF)NewBitmap);
   SurfObj->dhsurf = dhsurf;
   EngUnlockSurface(SurfObj);