Implement GLHelperReadbackSupport for GLHelper usage.

content/common/gpu/client/gl_helper.h

 // Copyright (c) 2012 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_COMMON_GPU_CLIENT_GL_HELPER_H_
 #define CONTENT_COMMON_GPU_CLIENT_GL_HELPER_H_
 
 #include "base/atomicops.h"
 #include "base/basictypes.h"
 #include "base/callback.h"
@@ skipping 126 matching lines @@
 
   ~ScopedFlush() { gl_->Flush(); }
 
  private:
   gpu::gles2::GLES2Interface* gl_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedFlush);
 };
 
 class ReadbackYUVInterface;
+class GLHelperReadbackSupport;
 
 // Provides higher level operations on top of the gpu::gles2::GLES2Interface
 // interfaces.
 class CONTENT_EXPORT GLHelper {
  public:
   GLHelper(gpu::gles2::GLES2Interface* gl,
            gpu::ContextSupport* context_support);
   ~GLHelper();
 
   enum ScalerQuality {
@@ skipping 113 matching lines @@
   // Resizes the texture's size to |size|.
   void ResizeTexture(GLuint texture, const gfx::Size& size);
 
   // Copies the framebuffer data given in |rect| to |texture|.
   void CopyTextureSubImage(GLuint texture, const gfx::Rect& rect);
 
   // Copies the all framebuffer data to |texture|. |size| specifies the
   // size of the framebuffer.
   void CopyTextureFullImage(GLuint texture, const gfx::Size& size);
 
-  // Check whether rgb565 readback is supported or not.
-  bool CanUseRgb565Readback();
-
   // A scaler will cache all intermediate textures and programs
   // needed to scale from a specified size to a destination size.
   // If the source or destination sizes changes, you must create
   // a new scaler.
   class CONTENT_EXPORT ScalerInterface {
    public:
     ScalerInterface() {}
     virtual ~ScalerInterface() {}
 
     // Note that the src_texture will have the min/mag filter set to GL_LINEAR
@@ skipping 28 matching lines @@
                                                   const gfx::Rect& src_subrect,
                                                   const gfx::Size& dst_size,
                                                   const gfx::Rect& dst_subrect,
                                                   bool flip_vertically,
                                                   bool use_mrt);
 
   // Returns the maximum number of draw buffers available,
   // 0 if GL_EXT_draw_buffers is not available.
   GLint MaxDrawBuffers();
 
+  // Checks whether the readbback is supported for texture with the
+  // matching config. This doesnt check for cross format readbacks.
+  bool IsReadbackConfigSupported(SkBitmap::Config texture_format);
+
  protected:
   class CopyTextureToImpl;
 
   // Creates |copy_texture_to_impl_| if NULL.
   void InitCopyTextToImpl();
   // Creates |scaler_impl_| if NULL.
   void InitScalerImpl();
 
   gpu::gles2::GLES2Interface* gl_;
   gpu::ContextSupport* context_support_;
   scoped_ptr<CopyTextureToImpl> copy_texture_to_impl_;
   scoped_ptr<GLHelperScaling> scaler_impl_;
-  bool initialized_565_format_check_;
-  bool support_565_format_;
+  scoped_ptr<GLHelperReadbackSupport> readback_support_;
 
   DISALLOW_COPY_AND_ASSIGN(GLHelper);
 };
 
 // Similar to a ScalerInterface, a yuv readback pipeline will
 // cache a scaler and all intermediate textures and frame buffers
 // needed to scale, crop, letterbox and read back a texture from
 // the GPU into CPU-accessible RAM. A single readback pipeline
 // can handle multiple outstanding readbacks at the same time, but
 // if the source or destination sizes change, you'll need to create
 // a new readback pipeline.
 class CONTENT_EXPORT ReadbackYUVInterface {
  public:
   ReadbackYUVInterface() {}
   virtual ~ReadbackYUVInterface() {}
 
   // Note that |target| must use YV12 format.
   virtual void ReadbackYUV(const gpu::Mailbox& mailbox,
                            uint32 sync_point,
                            const scoped_refptr<media::VideoFrame>& target,
                            const base::Callback<void(bool)>& callback) = 0;
   virtual GLHelper::ScalerInterface* scaler() = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_CLIENT_GL_HELPER_H_