Add allowSynchronousMode to SurfaceTexture constructor.

Change-Id: I54f30a3c16bbe6b813f3bcd1d389da5627531304
diff --git a/include/gui/SurfaceTexture.h b/include/gui/SurfaceTexture.h
index 9294df6..e558dfd 100644
--- a/include/gui/SurfaceTexture.h
+++ b/include/gui/SurfaceTexture.h
@@ -56,7 +56,7 @@
 
     // tex indicates the name OpenGL texture to which images are to be streamed.
     // This texture name cannot be changed once the SurfaceTexture is created.
-    SurfaceTexture(GLuint tex);
+    SurfaceTexture(GLuint tex, bool allowSynchronousMode = true);
 
     virtual ~SurfaceTexture();
 
@@ -361,6 +361,9 @@
     // mSynchronousMode whether we're in synchronous mode or not
     bool mSynchronousMode;
 
+    // mAllowSynchronousMode whether we allow synchronous mode or not
+    const bool mAllowSynchronousMode;
+
     // mDequeueCondition condition used for dequeueBuffer in synchronous mode
     mutable Condition mDequeueCondition;