Revert of Pepper takes ownership of a mailbox before passing it to the texture layer.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 11d39c200ab6ca9348e03803f1ac852e05ed073d..c9e8470b6cca2e031b61a22bbd12e737b48a5c55 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -593,8 +593,7 @@
                   const std::vector<int32_t>& attribs) override;
   void Destroy(bool have_context) override;
   void SetSurface(const scoped_refptr<gfx::GLSurface>& surface) override;
-  void TakeFrontBuffer(const Mailbox& mailbox) override;
-  void ReturnFrontBuffer(const Mailbox& mailbox, bool is_lost) override;
+  void ProduceFrontBuffer(const Mailbox& mailbox) override;
   bool ResizeOffscreenFrameBuffer(const gfx::Size& size) override;
   void UpdateParentTextureInfo();
   bool MakeCurrent() override;
@@ -1994,33 +1993,6 @@
   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 {
-    std::unique_ptr<BackTexture> back_texture;
-    scoped_refptr<TextureRef> texture_ref;
-    bool in_use;
-  };
-  std::vector<SavedBackTexture> saved_back_textures_;
-
-  // If there's a SavedBackTexture that's not in use, takes that. Otherwise,
-  // generates a new back texture.
-  void CreateBackTexture();
-  size_t create_back_texture_count_for_test_ = 0;
-
-  // Releases all saved BackTextures that are not in use by a client.
-  void ReleaseNotInUseBackTextures();
-
-  // Releases all saved BackTextures.
-  void ReleaseAllBackTextures();
-
-  size_t GetSavedBackTextureCountForTest() override;
-  size_t GetCreatedBackTextureCountForTest() override;
 
   // The copy that is used as the destination for multi-sample resolves.
   std::unique_ptr<BackFramebuffer> offscreen_resolved_frame_buffer_;
@@ -4095,7 +4067,6 @@
     offscreen_saved_color_texture_->Invalidate();
     offscreen_saved_color_texture_info_ = NULL;
   }
-  ReleaseAllBackTextures();
   if (have_context) {
     if (copy_texture_CHROMIUM_.get()) {
       copy_texture_CHROMIUM_->Destroy();
@@ -4234,12 +4205,11 @@
   RestoreCurrentFramebufferBindings();
 }
 
-void GLES2DecoderImpl::TakeFrontBuffer(const Mailbox& mailbox) {
+void GLES2DecoderImpl::ProduceFrontBuffer(const Mailbox& mailbox) {
   if (!offscreen_saved_color_texture_.get()) {
-    DLOG(ERROR) << "Called TakeFrontBuffer on a non-offscreen context";
-    return;
-  }
-
+    LOG(ERROR) << "Called ProduceFrontBuffer on a non-offscreen context";
+    return;
+  }
   if (!offscreen_saved_color_texture_info_.get()) {
     GLuint service_id = offscreen_saved_color_texture_->id();
     offscreen_saved_color_texture_info_ = TextureRef::Create(
@@ -4248,92 +4218,8 @@
                                  GL_TEXTURE_2D);
     UpdateParentTextureInfo();
   }
-
   mailbox_manager()->ProduceTexture(
       mailbox, offscreen_saved_color_texture_info_->texture());
-
-  // Save the BackTexture and TextureRef.
-  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();
-}
-
-void GLES2DecoderImpl::ReturnFrontBuffer(const Mailbox& mailbox, bool is_lost) {
-  Texture* texture = mailbox_manager()->ConsumeTexture(mailbox);
-  for (auto it = saved_back_textures_.begin(); it != saved_back_textures_.end();
-       ++it) {
-    if (texture != it->texture_ref->texture())
-      continue;
-
-    if (is_lost || it->back_texture->size() != offscreen_size_) {
-      it->back_texture->Invalidate();
-      saved_back_textures_.erase(it);
-      return;
-    }
-
-    it->in_use = false;
-    return;
-  }
-
-  DLOG(ERROR) << "Attempting to return a frontbuffer that was not saved.";
-}
-
-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;
-    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);
-  offscreen_saved_frame_buffer_->AttachRenderTexture(
-      offscreen_saved_color_texture_.get());
-}
-
-void GLES2DecoderImpl::ReleaseNotInUseBackTextures() {
-  for (auto& saved_back_texture : saved_back_textures_) {
-    if (!saved_back_texture.in_use)
-      saved_back_texture.back_texture->Invalidate();
-  }
-
-  std::remove_if(saved_back_textures_.begin(), saved_back_textures_.end(),
-                 [](const SavedBackTexture& saved_back_texture) {
-                   return !saved_back_texture.in_use;
-                 });
-}
-
-void GLES2DecoderImpl::ReleaseAllBackTextures() {
-  for (auto& saved_back_texture : saved_back_textures_) {
-    // The texture will be destroyed by texture_ref's destructor.
-    DCHECK(saved_back_texture.texture_ref);
-    saved_back_texture.back_texture->Invalidate();
-  }
-  saved_back_textures_.clear();
-}
-
-size_t GLES2DecoderImpl::GetSavedBackTextureCountForTest() {
-  return saved_back_textures_.size();
-}
-
-size_t GLES2DecoderImpl::GetCreatedBackTextureCountForTest() {
-  return create_back_texture_count_for_test_;
 }
 
 bool GLES2DecoderImpl::ResizeOffscreenFrameBuffer(const gfx::Size& size) {
@@ -12829,10 +12715,6 @@
         glFinish();
       }
 
-      // The size has changed, so none of the cached BackTextures are useful
-      // anymore.
-      ReleaseNotInUseBackTextures();
-
       // Allocate the offscreen saved color texture.
       DCHECK(offscreen_saved_color_format_);
       offscreen_saved_color_texture_->AllocateStorage(