[Reland 1] Pepper takes ownership of a mailbox before passing it to the texture layer.

content/renderer/pepper/pepper_plugin_instance_impl.cc

Index: content/renderer/pepper/pepper_plugin_instance_impl.cc
diff --git a/content/renderer/pepper/pepper_plugin_instance_impl.cc b/content/renderer/pepper/pepper_plugin_instance_impl.cc
index 17925e9d2383f1e48448b015dbaa87315196fc16..cf7521b980d81209455ebec1449ae88a347cadd0 100644
--- a/content/renderer/pepper/pepper_plugin_instance_impl.cc
+++ b/content/renderer/pepper/pepper_plugin_instance_impl.cc
@@ -781,22 +781,60 @@ void PepperPluginInstanceImpl::ScrollRect(int dx,
   }
 }
 
-void PepperPluginInstanceImpl::CommitBackingTexture() {
+void PepperPluginInstanceImpl::CommitTextureMailbox(
+    const cc::TextureMailbox& texture_mailbox) {
+  if (committed_texture_.IsValid() && !IsTextureInUse(committed_texture_)) {
+    bound_graphics_3d_->ReturnFrontBuffer(
+        committed_texture_.mailbox(), committed_texture_consumed_sync_token_,
+        false);
+  }
+
+  committed_texture_ = texture_mailbox;
+  committed_texture_consumed_sync_token_ = gpu::SyncToken();
+
   if (!texture_layer_) {
     UpdateLayer(true);
     return;
   }
 
-  gpu::Mailbox mailbox;
-  gpu::SyncToken sync_token;
-  bound_graphics_3d_->GetBackingMailbox(&mailbox, &sync_token);
-  DCHECK(!mailbox.IsZero());
-  DCHECK(sync_token.HasData());
-  texture_layer_->SetTextureMailboxWithoutReleaseCallback(
-      cc::TextureMailbox(mailbox, sync_token, GL_TEXTURE_2D));
+  PassCommittedTextureToTextureLayer();
   texture_layer_->SetNeedsDisplay();
 }
 
+void PepperPluginInstanceImpl::PassCommittedTextureToTextureLayer() {
+  DCHECK(bound_graphics_3d_);
+
+  if (!committed_texture_.IsValid())
+    return;
+
+  std::unique_ptr<cc::SingleReleaseCallback> callback(
+      cc::SingleReleaseCallback::Create(base::Bind(
+          &PepperPluginInstanceImpl::FinishedConsumingCommittedTexture,
+          weak_factory_.GetWeakPtr(), committed_texture_)));
+
+  IncrementTextureReferenceCount(committed_texture_);
+  texture_layer_->SetTextureMailbox(committed_texture_, std::move(callback));
+}
+
+void PepperPluginInstanceImpl::FinishedConsumingCommittedTexture(
+    const cc::TextureMailbox& texture_mailbox,
+    const gpu::SyncToken& sync_token,
+    bool is_lost) {
+  bool removed = DecrementTextureReferenceCount(texture_mailbox);
+  bool is_committed_texture =
+      committed_texture_.mailbox() == texture_mailbox.mailbox();
+
+  if (is_committed_texture && !is_lost) {
+    committed_texture_consumed_sync_token_ = sync_token;
+    return;
+  }
+
+  if (removed && !is_committed_texture) {
+    bound_graphics_3d_->ReturnFrontBuffer(texture_mailbox.mailbox(), sync_token,
+                                          is_lost);
+  }
+}
+
 void PepperPluginInstanceImpl::InstanceCrashed() {
   // Force free all resources and vars.
   HostGlobals::Get()->InstanceCrashed(pp_instance());
@@ -2017,12 +2055,7 @@ void PepperPluginInstanceImpl::UpdateLayer(bool force_creation) {
   if (!container_)
     return;
 
-  gpu::Mailbox mailbox;
-  gpu::SyncToken sync_token;
-  if (bound_graphics_3d_.get()) {
-    bound_graphics_3d_->GetBackingMailbox(&mailbox, &sync_token);
-  }
-  bool want_3d_layer = !mailbox.IsZero() && sync_token.HasData();
+  bool want_3d_layer = !!bound_graphics_3d_.get();
   bool want_2d_layer = !!bound_graphics_2d_platform_;
   bool want_texture_layer = want_3d_layer || want_2d_layer;
   bool want_compositor_layer = !!bound_compositor_;
@@ -2061,8 +2094,8 @@ void PepperPluginInstanceImpl::UpdateLayer(bool force_creation) {
       DCHECK(bound_graphics_3d_.get());
       texture_layer_ = cc::TextureLayer::CreateForMailbox(NULL);
       opaque = bound_graphics_3d_->IsOpaque();
-      texture_layer_->SetTextureMailboxWithoutReleaseCallback(
-          cc::TextureMailbox(mailbox, sync_token, GL_TEXTURE_2D));
+
+      PassCommittedTextureToTextureLayer();
     } else {
       DCHECK(bound_graphics_2d_platform_);
       texture_layer_ = cc::TextureLayer::CreateForMailbox(this);
@@ -3353,4 +3386,47 @@ void PepperPluginInstanceImpl::ConvertDIPToViewport(gfx::Rect* rect) const {
   rect->set_height(rect->height() / viewport_to_dip_scale_);
 }
 
+void PepperPluginInstanceImpl::IncrementTextureReferenceCount(
+    const cc::TextureMailbox& mailbox) {
+  auto it =
+      std::find_if(texture_ref_counts_.begin(), texture_ref_counts_.end(),
+                   [&mailbox](const TextureMailboxRefCount& ref_count) {
+                     return ref_count.first.mailbox() == mailbox.mailbox();
+                   });
+  if (it == texture_ref_counts_.end()) {
+    texture_ref_counts_.push_back(std::make_pair(mailbox, 1));
+    return;
+  }
+
+  it->second++;
+}
+
+bool PepperPluginInstanceImpl::DecrementTextureReferenceCount(
+    const cc::TextureMailbox& mailbox) {
+  auto it =
+      std::find_if(texture_ref_counts_.begin(), texture_ref_counts_.end(),
+                   [&mailbox](const TextureMailboxRefCount& ref_count) {
+                     return ref_count.first.mailbox() == mailbox.mailbox();
+                   });
+  DCHECK(it != texture_ref_counts_.end());
+
+  if (it->second == 1) {
+    texture_ref_counts_.erase(it);
+    return true;
+  }
+
+  it->second--;
+  return false;
+}
+
+bool PepperPluginInstanceImpl::IsTextureInUse(
+    const cc::TextureMailbox& mailbox) const {
+  auto it =
+      std::find_if(texture_ref_counts_.begin(), texture_ref_counts_.end(),
+                   [&mailbox](const TextureMailboxRefCount& ref_count) {
+                     return ref_count.first.mailbox() == mailbox.mailbox();
+                   });
+  return it != texture_ref_counts_.end();
+}
+
 }  // namespace content