Merge pull request #506 from pragmatrix/angle

ANGLE: keep the backbuffer's size updated when the window resizes

src/OpenTK/Platform/Egl/EglContext.cs

@@ -171,6 +171,19 @@ namespace OpenTK.Platform.Egl
             }
         }
 
+        public override void Update(IWindowInfo window)
+        {
+            MakeCurrent(window);
+            // ANGLE updates the width and height of the back buffer surfaces in the WaitClient function.
+            // So without this calling this function, the surface won't match the size of the window after it 
+            // was resized.
+            // https://bugs.chromium.org/p/angleproject/issues/detail?id=1438
+            if (!Egl.WaitClient())
+            {
+                Debug.Print("[Warning] Egl.WaitClient() failed. Error: {0}", Egl.GetError());
+            }
+        }
+
         #endregion
 
         #region IGraphicsContextInternal Members