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

content/browser/renderer_host/compositing_iosurface_transformer_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_TRANSFORMER_MAC_H_
+#define CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_TRANSFORMER_MAC_H_
+
+#include <OpenGL/gl.h>
+
+#include "base/basictypes.h"
+#include "content/browser/renderer_host/compositing_iosurface_shader_programs_mac.h"
+#include "ui/gfx/size.h"
+
+namespace gfx {
+class Rect;
+}  // namespace gfx
+
+namespace content {
+
+// Provides useful image filtering operations that are implemented efficiently
+// using OpenGL shader programs.
+//
+// Note: All methods assume to be called within an active OpenGL context.
+class CompositingIOSurfaceTransformer {
+ public:
+  // Construct a transformer that always uses the given parameters for texture
+  // bindings.  |texture_target| is one of the valid enums to use with
+  // glBindTexture().
+  // |src_texture_needs_y_flip| is true when the |src_texture| argument to any
+  // of the methods below uses upside-down Y coordinates.
+  // |shader_program_cache| is not owned by this instance.
+  CompositingIOSurfaceTransformer(
+      GLenum texture_target, bool src_texture_needs_y_flip,
+      CompositingIOSurfaceShaderPrograms* shader_program_cache);
+
+  ~CompositingIOSurfaceTransformer();
+
+  // Delete any references to currently-cached OpenGL objects.  This must be
+  // called within the OpenGL context just before destruction.
+  void ReleaseCachedGLObjects();
+
+  // Resize using bilinear interpolation.  Returns false on error.  Otherwise,
+  // the |texture| argument will point to the result.  Ownership of the returned
+  // |texture| remains with CompositingIOSurfaceTransformer (i.e., the caller
+  // must not delete this texture).  The |texture| remains valid until the next
+  // call to ResizeBilinear() or ReleaseCachedGLObjects().
+  //
+  // If the src and dst sizes are identical, this becomes a simple copy into a
+  // new texture.
+  //
+  // Note: This implementation is faulty in that minifications by more than 2X
+  // will undergo aliasing.
+  bool ResizeBilinear(GLuint src_texture, const gfx::Rect& src_subrect,
+                      const gfx::Size& dst_size, GLuint* texture);
+
+  // Color format conversion from RGB to planar YV12 (also known as YUV420).
+  //
+  // YV12 is effectively a twelve bit per pixel format consisting of a full-
+  // size y (luminance) plane and half-width, half-height u and v (blue and
+  // red chrominance) planes.  This method will return three off-screen
+  // textures, one for each plane, via the output arguments |texture_y|,
+  // |texture_u|, and |texture_v|.  While the textures are in GL_RGBA format,
+  // they should be interpreted as the appropriate single-byte, planar format
+  // after reading the pixel data.  The output arguments |packed_y_size| and
+  // |packed_uv_size| follow from these special semantics: They represent the
+  // size of their corresponding texture, if it was to be treated like RGBA
+  // pixel data.  That means their widths are in terms of "quads," where one
+  // quad contains 4 Y (or U or V) pixels.
+  //
+  // Ownership of the returned textures remains with
+  // CompositingIOSurfaceTransformer (i.e., the caller must not delete the
+  // textures).  The textures remain valid until the next call to
+  // TransformRGBToYV12() or ReleaseCachedGLObjects().
+  //
+  // If |src_subrect|'s size does not match |dst_size|, the source will be
+  // bilinearly interpolated during conversion.
+  //
+  // Returns true if successful, and the caller is responsible for deleting the
+  // output textures.
+  bool TransformRGBToYV12(
+      GLuint src_texture, const gfx::Rect& src_subrect,
+      const gfx::Size& dst_size,
+      GLuint* texture_y, GLuint* texture_u, GLuint* texture_v,
+      gfx::Size* packed_y_size, gfx::Size* packed_uv_size);
+
+ private:
+  enum CachedTexture {
+    RGBA_OUTPUT = 0,
+    Y_PLANE_OUTPUT,
+    UUVV_INTERMEDIATE,
+    U_PLANE_OUTPUT,
+    V_PLANE_OUTPUT,
+    NUM_CACHED_TEXTURES
+  };
+
+  // If necessary, generate the texture and/or resize it to the given |size|.
+  void PrepareTexture(CachedTexture which, const gfx::Size& size);
+
+  // If necessary, generate a framebuffer object to be used as an intermediate
+  // destination for drawing.
+  void PrepareFramebuffer();
+
+  // Target to bind all input and output textures to (which defines the type of
+  // textures being created and read).  Generally, this is
+  // GL_TEXTURE_RECTANGLE_ARB.
+  const GLenum texture_target_;
+  const bool src_texture_needs_y_flip_;
+  CompositingIOSurfaceShaderPrograms* const shader_program_cache_;
+
+  // Cached OpenGL objects.
+  GLuint textures_[NUM_CACHED_TEXTURES];
+  gfx::Size texture_sizes_[NUM_CACHED_TEXTURES];
+  GLuint frame_buffer_;
+
+  // Auto-detected and set once in the constructor.
+  bool system_supports_multiple_draw_buffers_;
+
+  DISALLOW_COPY_AND_ASSIGN(CompositingIOSurfaceTransformer);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_COMPOSITING_IOSURFACE_TRANSFORMER_MAC_H_