gpu: Fix a bug in the new ReturnFrontBuffer() path for pepper.

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 <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 2030 matching lines @@
   std::unique_ptr<BackTexture> offscreen_target_color_texture_;
   std::unique_ptr<BackRenderbuffer> offscreen_target_color_render_buffer_;
   std::unique_ptr<BackRenderbuffer> offscreen_target_depth_render_buffer_;
   std::unique_ptr<BackRenderbuffer> offscreen_target_stencil_render_buffer_;
   GLenum offscreen_target_color_format_;
   GLenum offscreen_target_depth_format_;
   GLenum offscreen_target_stencil_format_;
   GLsizei offscreen_target_samples_;
   GLboolean offscreen_target_buffer_preserved_;
 
-  // The copy that is saved when SwapBuffers is called.
+  // The saved copy of the backbuffer after a call to SwapBuffers.
+  std::unique_ptr<BackTexture> offscreen_saved_color_texture_;
+
+  // For simplicity, |offscreen_saved_color_texture_| is always bound to
+  // |offscreen_saved_frame_buffer_|.
   std::unique_ptr<BackFramebuffer> offscreen_saved_frame_buffer_;
-  std::unique_ptr<BackTexture> offscreen_saved_color_texture_;
   scoped_refptr<TextureRef>
       offscreen_saved_color_texture_info_;
 
   // When a client requests ownership of the swapped front buffer, all
   // information is saved in this structure, and |in_use| is set to true. When a
   // client releases ownership, |in_use| is set to false.
   //
   // An instance of this struct, with |in_use| = false may be reused instead of
   // making a new BackTexture.
   struct SavedBackTexture {
@@ skipping 2151 matching lines @@
   state_.bound_transform_feedback_buffer = nullptr;
   state_.bound_uniform_buffer = nullptr;
   framebuffer_state_.bound_read_framebuffer = nullptr;
   framebuffer_state_.bound_draw_framebuffer = nullptr;
   state_.bound_renderbuffer = nullptr;
   state_.bound_transform_feedback = nullptr;
   state_.default_transform_feedback = nullptr;
   state_.indexed_uniform_buffer_bindings = nullptr;
 
   if (offscreen_saved_color_texture_info_.get()) {
-    DCHECK(offscreen_target_color_texture_);
+    DCHECK(offscreen_saved_color_texture_);
     DCHECK_EQ(offscreen_saved_color_texture_info_->service_id(),
               offscreen_saved_color_texture_->id());
     offscreen_saved_color_texture_->Invalidate();
     offscreen_saved_color_texture_info_ = NULL;
   }
   ReleaseAllBackTextures();
   if (have_context) {
     if (copy_texture_CHROMIUM_.get()) {
       copy_texture_CHROMIUM_->Destroy();
       copy_texture_CHROMIUM_.reset();
@@ skipping 161 matching lines @@
     offscreen_saved_color_texture_info_ = TextureRef::Create(
         texture_manager(), 0, service_id);
     texture_manager()->SetTarget(offscreen_saved_color_texture_info_.get(),
                                  GL_TEXTURE_2D);
     UpdateParentTextureInfo();
   }
 
   mailbox_manager()->ProduceTexture(
       mailbox, offscreen_saved_color_texture_info_->texture());
 
-  // Save the BackTexture and TextureRef.
+  // Save the BackTexture and TextureRef. There's no need to update
+  // |offscreen_saved_frame_buffer_| since CreateBackTexture() will take care of
+  // that.
   SavedBackTexture save;
   save.back_texture.swap(offscreen_saved_color_texture_);
   save.texture_ref = offscreen_saved_color_texture_info_;
   offscreen_saved_color_texture_info_ = nullptr;
   save.in_use = true;
   saved_back_textures_.push_back(std::move(save));
 
   CreateBackTexture();
 }
 
@@ skipping 20 matching lines @@
 void GLES2DecoderImpl::CreateBackTexture() {
   for (auto it = saved_back_textures_.begin(); it != saved_back_textures_.end();
        ++it) {
     if (it->in_use)
       continue;
 
     if (it->back_texture->size() != offscreen_size_)
       continue;
     offscreen_saved_color_texture_ = std::move(it->back_texture);
     offscreen_saved_color_texture_info_ = it->texture_ref;
+    offscreen_saved_frame_buffer_->AttachRenderTexture(
+        offscreen_saved_color_texture_.get());
     saved_back_textures_.erase(it);
     return;
   }
 
   ++create_back_texture_count_for_test_;
   offscreen_saved_color_texture_.reset(
       new BackTexture(memory_tracker(), &state_));
   offscreen_saved_color_texture_->Create();
   offscreen_saved_color_texture_->AllocateStorage(
       offscreen_size_, offscreen_saved_color_format_, false);
@@ skipping 8773 matching lines @@
             offscreen_saved_color_format_);
       } else {
         // Flip the textures in the parent context via the texture manager.
         if (!!offscreen_saved_color_texture_info_.get())
           offscreen_saved_color_texture_info_->texture()->
               SetServiceId(offscreen_target_color_texture_->id());
 
         offscreen_saved_color_texture_.swap(offscreen_target_color_texture_);
         offscreen_target_frame_buffer_->AttachRenderTexture(
             offscreen_target_color_texture_.get());
+        offscreen_saved_frame_buffer_->AttachRenderTexture(
+            offscreen_saved_color_texture_.get());
       }
 
       // Ensure the side effects of the copy are visible to the parent
       // context. There is no need to do this for ANGLE because it uses a
       // single D3D device for all contexts.
       if (!feature_info_->gl_version_info().is_angle)
         glFlush();
     }
   } else if (supports_async_swap_) {
     TRACE_EVENT_ASYNC_BEGIN0("cc", "GLES2DecoderImpl::AsyncSwapBuffers", this);
@@ skipping 3563 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 "base/macros.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu