This is initial API support required for enabling SurfaceTexture backed zero-copy for Android

ui/gl/android/surface_texture.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GL_ANDROID_SURFACE_TEXTURE_H_
 #define UI_GL_ANDROID_SURFACE_TEXTURE_H_
 
 #include <jni.h>
 
 #include "base/android/scoped_java_ref.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "ui/gl/gl_export.h"
 
 struct ANativeWindow;
 
 namespace gfx {
 
 // This class serves as a bridge for native code to call java functions inside
 // android SurfaceTexture class.
 class GL_EXPORT SurfaceTexture
     : public base::RefCountedThreadSafe<SurfaceTexture>{
  public:
-  explicit SurfaceTexture(int texture_id);
+  SurfaceTexture(int texture_id, bool single_buffer_mode);
 
   // Set the listener callback, which will be invoked on the same thread that
   // is being called from here for registration.
   // Note: Since callbacks come in from Java objects that might outlive objects
   // being referenced from the callback, the only robust way here is to create
   // the callback from a weak pointer to your object.
   void SetFrameAvailableCallback(const base::Closure& callback);
 
   // Update the texture image to the most recent frame from the image stream.
   void UpdateTexImage();
 
+  // Release the texture content. This is needed in single buffered mode
+  // to allow the image content producer to take ownership of the image buffer.

[bulach, 2014/03/10 12:32:31]

should we comment that this is only available since KitKat?

[reveman, 2014/03/10 13:33:05]

I don't think so. We can add a comment about this only being supported in single
buffer mode but we should not expose the idea of android versions unless the
client of this API can also use that to determine if single buffered mode is
supported.

+  void ReleaseTexImage();
+
   // Retrieve the 4x4 texture coordinate transform matrix associated with the
   // texture image set by the most recent call to updateTexImage.
   void GetTransformMatrix(float mtx[16]);
 
   // Set the default size of the image buffers.
   void SetDefaultBufferSize(int width, int height);
 
   // Attach the SurfaceTexture to the texture currently bound to
   // GL_TEXTURE_EXTERNAL_OES.
   void AttachToGLContext();
@@ skipping 19 matching lines @@
 
   // Java SurfaceTexture instance.
   base::android::ScopedJavaGlobalRef<jobject> j_surface_texture_;
 
   DISALLOW_COPY_AND_ASSIGN(SurfaceTexture);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_ANDROID_SURFACE_TEXTURE_H_