gpu: Add CopyTexImage function to GLImage API.

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // 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.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 10110 matching lines @@
     }
 
     texture_manager()->SetLevelInfo(
         dest_texture_ref, GL_TEXTURE_2D, level, internal_format, source_width,
         source_height, 1, 0, internal_format, dest_type, true);
   } else {
     texture_manager()->SetLevelCleared(
         dest_texture_ref, GL_TEXTURE_2D, level, true);
   }
 
+  ScopedModifyPixels modify(dest_texture_ref);
+
+  // Try using GLImage::CopyTexImage when possible.
+  bool unpack_premultiply_alpha_change =
+      unpack_premultiply_alpha_ ^ unpack_unpremultiply_alpha_;
+  if (image && !unpack_flip_y_ && !unpack_premultiply_alpha_change && !level) {
+    glBindTexture(GL_TEXTURE_2D, dest_texture->service_id());
+    if (image->CopyTexImage(GL_TEXTURE_2D))
+      return;
+  }
+
   DoWillUseTexImageIfNeeded(source_texture, source_texture->target());
-  ScopedModifyPixels modify(dest_texture_ref);
 
   // GL_TEXTURE_EXTERNAL_OES texture requires apply a transform matrix
   // before presenting.
   if (source_texture->target() == GL_TEXTURE_EXTERNAL_OES) {
     // TODO(hkuang): get the StreamTexture transform matrix in GPU process
     // instead of using default matrix crbug.com/226218.
     const static GLfloat default_matrix[16] = {1.0f, 0.0f, 0.0f, 0.0f,
                                                0.0f, 1.0f, 0.0f, 0.0f,
                                                0.0f, 0.0f, 1.0f, 0.0f,
                                                0.0f, 0.0f, 0.0f, 1.0f};
@@ skipping 874 matching lines @@
   }
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu