EGL: default to swap interval 1

This change explicitly sets swap interval 1 on the window when an
EGLSurface is created to render to it.

Change-Id: I91eb29dbee3ae4a55076b921f084d503fbe94e03
diff --git a/include/gui/SurfaceTexture.h b/include/gui/SurfaceTexture.h
index 27d863d..15c2bab 100644
--- a/include/gui/SurfaceTexture.h
+++ b/include/gui/SurfaceTexture.h
@@ -202,6 +202,10 @@
     // getCurrentScalingMode returns the scaling mode of the current buffer
     uint32_t getCurrentScalingMode() const;
 
+    // isSynchronousMode returns whether the SurfaceTexture is currently in
+    // synchronous mode.
+    bool isSynchronousMode() const;
+
     // abandon frees all the buffers and puts the SurfaceTexture into the
     // 'abandoned' state.  Once put in this state the SurfaceTexture can never
     // leave it.  When in the 'abandoned' state, all methods of the