Query the preferred readback config in CopyFromBackingStore

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 312 matching lines @@
                                                   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);
 
+  // Returns the preffered readback-config based on the platform criteria.
+  SkBitmap::Config PreferredReadbackFormat();
+
  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_;
@@ skipping 20 matching lines @@
   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_