Revert of Introduce components/display_compositor

content/browser/compositor/gl_helper_readback_support.h

+// Copyright 2014 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_COMPOSITOR_GL_HELPER_READBACK_SUPPORT_H_
+#define CONTENT_BROWSER_COMPOSITOR_GL_HELPER_READBACK_SUPPORT_H_
+
+#include <stddef.h>
+
+#include <vector>
+
+#include "content/browser/compositor/gl_helper.h"
+
+namespace content {
+
+class CONTENT_EXPORT GLHelperReadbackSupport {
+ public:
+  enum FormatSupport { SUPPORTED, SWIZZLE, NOT_SUPPORTED };
+
+  GLHelperReadbackSupport(gpu::gles2::GLES2Interface* gl);
+
+  ~GLHelperReadbackSupport();
+
+  // For a given color type retrieve whether readback is supported and if so
+  // how it should be performed. The |format|, |type| and |bytes_per_pixel| are
+  // the values that should be used with glReadPixels to facilitate the
+  // readback. If |can_swizzle| is true then this method will return SWIZZLE if
+  // the data needs to be swizzled before using the returned |format| otherwise
+  // the method will return SUPPORTED to indicate that readback is permitted of
+  // this color othewise NOT_SUPPORTED will be returned.  This method always
+  // overwrites the out values irrespective of the return value.
+  FormatSupport GetReadbackConfig(SkColorType color_type,
+                                  bool can_swizzle,
+                                  GLenum* format,
+                                  GLenum* type,
+                                  size_t* bytes_per_pixel);
+  // Provides the additional readback format/type pairing for a render target
+  // of a given format/type pairing
+  void GetAdditionalFormat(GLenum format,
+                           GLenum type,
+                           GLenum* format_out,
+                           GLenum* type_out);
+
+ private:
+  struct FormatCacheEntry {
+    GLenum format;
+    GLenum type;
+    GLenum read_format;
+    GLenum read_type;
+  };
+
+  // This populates the format_support_table with the list of supported
+  // formats.
+  void InitializeReadbackSupport();
+
+  // This api is called  once per format and it is done in the
+  // InitializeReadbackSupport. We should not use this any where
+  // except the InitializeReadbackSupport.Calling this at other places
+  // can distrub the state of normal gl operations.
+  void CheckForReadbackSupport(SkColorType texture_format);
+
+  // Helper functions for checking the supported texture formats.
+  // Avoid using this API in between texture operations, as this does some
+  // teture opertions (bind, attach) internally.
+  bool SupportsFormat(GLenum format, GLenum type);
+
+  FormatSupport format_support_table_[kLastEnum_SkColorType + 1];
+
+  gpu::gles2::GLES2Interface* gl_;
+  std::vector<struct FormatCacheEntry> format_cache_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_COMPOSITOR_GL_HELPER_READBACK_SUPPORT_H_