Implement external stencil for Android WebView

android_webview/browser/scoped_app_gl_state_restore.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.
 
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 
 namespace gfx {
 class GLContext;
 }
 
 namespace android_webview {
 
 namespace internal {
 class ScopedAppGLStateRestoreImpl;
 }
 
+struct StencilState {
+  unsigned char stencil_test_enabled;
+  int stencil_front_func;
+  int stencil_front_ref;
+  int stencil_front_mask;
+  int stencil_back_func;
+  int stencil_back_ref;
+  int stencil_back_mask;
+  int stencil_clear;
+  int stencil_front_writemask;
+  int stencil_back_writemask;
+  int stencil_front_fail_op;
+  int stencil_front_z_fail_op;
+  int stencil_front_z_pass_op;
+  int stencil_back_fail_op;
+  int stencil_back_z_fail_op;
+  int stencil_back_z_pass_op;
+};
+
 // This class is not thread safe and should only be used on the UI thread.
 class ScopedAppGLStateRestore {
  public:
   enum CallMode {
     MODE_DRAW,
     MODE_RESOURCE_MANAGEMENT,
   };
 
   explicit ScopedAppGLStateRestore(CallMode mode);
   ~ScopedAppGLStateRestore();
 
-  bool stencil_enabled() const;
+  StencilState stencil_state() const;
   int framebuffer_binding_ext() const;
 
  private:
   scoped_ptr<internal::ScopedAppGLStateRestoreImpl> impl_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedAppGLStateRestore);
 };
 
 }  // namespace android_webview