SurfaceTexture: add the abandon method.

This change adds the 'abandon' method to the SurfaceTexture C++ class.
This method may be used to put the SurfaceTexture in an abandoned state,
causing all ISurfaceTexture methods to fail.

Change-Id: Ibd261f7b73f44e2bec36a8508bf92113cfb7cf95
diff --git a/libs/gui/SurfaceTextureClient.cpp b/libs/gui/SurfaceTextureClient.cpp
index 688b99b..df0ad5a 100644
--- a/libs/gui/SurfaceTextureClient.cpp
+++ b/libs/gui/SurfaceTextureClient.cpp
@@ -148,10 +148,11 @@
     }
 
     if ((result & ISurfaceTexture::BUFFER_NEEDS_REALLOCATION) || gbuf == 0) {
-        gbuf = mSurfaceTexture->requestBuffer(buf);
-        if (gbuf == 0) {
-            LOGE("dequeueBuffer: ISurfaceTexture::requestBuffer failed");
-            return NO_MEMORY;
+        result = mSurfaceTexture->requestBuffer(buf, &gbuf);
+        if (result != NO_ERROR) {
+            LOGE("dequeueBuffer: ISurfaceTexture::requestBuffer failed: %d",
+                    result);
+            return result;
         }
         mQueryWidth  = gbuf->width;
         mQueryHeight = gbuf->height;