Revert of Remove code used by --disable-delegated-renderer on Mac

content/browser/renderer_host/compositing_iosurface_shader_programs_mac.h

+// Copyright (c) 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 CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_SHADER_PROGRAMS_MAC_H_
+#define CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_SHADER_PROGRAMS_MAC_H_
+
+#include <OpenGL/gl.h>
+
+#include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
+
+namespace content {
+
+// Provides caching of the compile-and-link step for shader programs at runtime
+// since, once compiled and linked, the programs can be shared.  Callers invoke
+// one of the UseXXX() methods to glUseProgram() the program and have its
+// uniform variables bound with the given parameters.
+//
+// Note: All public methods must be invoked within the the same GL context!
+class CompositingIOSurfaceShaderPrograms {
+ public:
+  CompositingIOSurfaceShaderPrograms();
+  ~CompositingIOSurfaceShaderPrograms();
+
+  // Reset the cache, deleting any references to currently-cached shader
+  // programs.  This must be called within an active OpenGL context just before
+  // destruction.
+  void Reset();
+
+  // Begin using the "blit" program, which is set up to sample the texture at
+  // GL_TEXTURE_0.  Returns false on error.
+  bool UseBlitProgram();
+
+  // Begin using the program that just draws solid white very efficiently.
+  // Returns false on error.
+  bool UseSolidWhiteProgram();
+
+  // Begin using one of the two RGB-to-YV12 color conversion programs, as
+  // specified by |pass_number| 1 or 2.  The programs will sample the texture at
+  // GL_TEXTURE0, and account for scaling in the X direction by |texel_scale_x|.
+  // Returns false on error.
+  bool UseRGBToYV12Program(int pass_number, float texel_scale_x);
+
+  // |format| argument to use for glReadPixels() when reading back textures
+  // generated by the RGBToYV12 program.
+  GLenum rgb_to_yv12_output_format() const {
+    return rgb_to_yv12_output_format_;
+  }
+
+ protected:
+  FRIEND_TEST_ALL_PREFIXES(CompositingIOSurfaceTransformerTest,
+                           TransformsRGBToYV12);
+
+  // Side effect: Calls Reset(), deleting any cached programs.
+  void SetOutputFormatForTesting(GLenum format);
+
+ private:
+  enum { kNumShaderPrograms = 4 };
+
+  // Helper methods to cache uniform variable locations.
+  GLuint GetShaderProgram(int which);
+  void BindUniformTextureVariable(int which, int texture_unit_offset);
+  void BindUniformTexelScaleXVariable(int which, float texel_scale_x);
+
+  // Cached values for previously-compiled/linked shader programs, and the
+  // locations of their uniform variables.
+  GLuint shader_programs_[kNumShaderPrograms];
+  GLint texture_var_locations_[kNumShaderPrograms];
+  GLint texel_scale_x_var_locations_[kNumShaderPrograms];
+
+  // Byte order of the quads generated by the RGBToYV12 shader program.  Must
+  // always be GL_BGRA (default) or GL_RGBA (workaround case).
+  GLenum rgb_to_yv12_output_format_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompositingIOSurfaceShaderPrograms);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_SHADER_PROGRAMS_MAC_H_