Don't let blink compositor set contents_opaque for remote frames

Currently, the only case where remote frames let the blink compositor
set contents_opaque for a remote frame is when displaying the sad
tab graphic for a crashed frame. The sad tab graphic is not opaque,
and we shouldn't ever set contents_opaque on its layer, regardless of
the style of its containing <iframe> element.

Bug: 1069546

Change-Id: I04636d2b6cead84d224913563fd6e9bab34069d1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2606659Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Stefan Zager <szager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840045}

content/renderer/child_frame_compositing_helper.cc

@@ -42,10 +42,8 @@ void ChildFrameCompositingHelper::ChildFrameGone(
   crash_ui_layer_->SetMasksToBounds(true);
   crash_ui_layer_->SetIsDrawable(true);
 
-  bool prevent_contents_opaque_changes = false;
   bool is_surface_layer = false;
-  child_frame_compositor_->SetLayer(
-      crash_ui_layer_, prevent_contents_opaque_changes, is_surface_layer);
+  child_frame_compositor_->SetLayer(crash_ui_layer_, is_surface_layer);
 }
 
 void ChildFrameCompositingHelper::SetSurfaceId(
@@ -66,9 +64,7 @@ void ChildFrameCompositingHelper::SetSurfaceId(
 
   // TODO(lfg): Investigate if it's possible to propagate the information
   // about the child surface's opacity. https://crbug.com/629851.
-  bool prevent_contents_opaque_changes = true;
   child_frame_compositor_->SetLayer(surface_layer_,
-                                    prevent_contents_opaque_changes,
                                     true /* is_surface_layer */);
 
   UpdateVisibility(true);

content/renderer/child_frame_compositing_helper_unittest.cc

@@ -23,7 +23,6 @@ class MockChildFrameCompositor : public ChildFrameCompositor {
   cc::Layer* GetLayer() override { return layer_.get(); }
 
   void SetLayer(scoped_refptr<cc::Layer> layer,
-                bool prevent_contents_opaque_changes,
                 bool is_surface_layer) override {
     layer_ = std::move(layer);
   }

content/renderer/child_frame_compositor.h

@@ -20,7 +20,6 @@ class ChildFrameCompositor {
 
   // Passes ownership of a cc::Layer to the ChildFrameCompositor.
   virtual void SetLayer(scoped_refptr<cc::Layer> layer,
-                        bool prevent_contents_opaque_changes,
                         bool is_surface_layer) = 0;
 
   // Returns a sad page bitmap used when the child frame has crashed.

content/renderer/render_frame_proxy.cc

@@ -669,17 +669,14 @@ cc::Layer* RenderFrameProxy::GetLayer() {
 }
 
 void RenderFrameProxy::SetLayer(scoped_refptr<cc::Layer> layer,
-                                bool prevent_contents_opaque_changes,
                                 bool is_surface_layer) {
   // |ancestor_web_frame_widget_| can be null if this is a proxy for a remote
   // main frame, or a subframe of that proxy. However, we should not be setting
   // a layer on such a proxy (the layer is used for embedding a child proxy).
   DCHECK(ancestor_web_frame_widget_);
 
-  if (web_frame()) {
-    web_frame()->SetCcLayer(layer.get(), prevent_contents_opaque_changes,
-                            is_surface_layer);
-  }
+  if (web_frame())
+    web_frame()->SetCcLayer(layer.get(), is_surface_layer);
   embedded_layer_ = std::move(layer);
 }
 

content/renderer/render_frame_proxy.h

@@ -233,9 +233,7 @@ class CONTENT_EXPORT RenderFrameProxy : public IPC::Listener,
 
   // ChildFrameCompositor:
   cc::Layer* GetLayer() override;
-  void SetLayer(scoped_refptr<cc::Layer> layer,
-                bool prevent_contents_opaque_changes,
-                bool is_surface_layer) override;
+  void SetLayer(scoped_refptr<cc::Layer> layer, bool is_surface_layer) override;
   SkBitmap* GetSadPageBitmap() override;
 
   const viz::LocalSurfaceId& GetLocalSurfaceId() const;

third_party/blink/public/web/web_remote_frame.h

@@ -100,9 +100,7 @@ class WebRemoteFrame : public WebFrame {
       WebFrame* opener) = 0;
 
   // Layer for the in-process compositor.
-  virtual void SetCcLayer(cc::Layer*,
-                          bool prevent_contents_opaque_changes,
-                          bool is_surface_layer) = 0;
+  virtual void SetCcLayer(cc::Layer*, bool is_surface_layer) = 0;
 
   // Set security origin replicated from another process.
   virtual void SetReplicatedOrigin(

third_party/blink/renderer/core/frame/remote_frame.cc

@@ -242,7 +242,7 @@ bool RemoteFrame::DetachImpl(FrameDetachType type) {
   // of all these objects. Break the cycle by notifying of detachment.
   To<RemoteDOMWindow>(dom_window_.Get())->FrameDetached();
   if (cc_layer_)
-    SetCcLayer(nullptr, false, false);
+    SetCcLayer(nullptr, false);
   receiver_.reset();
   main_frame_receiver_.reset();
 
@@ -772,13 +772,10 @@ bool RemoteFrame::IsIgnoredForHitTest() const {
          !visible_to_hit_testing_;
 }
 
-void RemoteFrame::SetCcLayer(cc::Layer* cc_layer,
-                             bool prevent_contents_opaque_changes,
-                             bool is_surface_layer) {
+void RemoteFrame::SetCcLayer(cc::Layer* cc_layer, bool is_surface_layer) {
   DCHECK(Owner());
 
   cc_layer_ = cc_layer;
-  prevent_contents_opaque_changes_ = prevent_contents_opaque_changes;
   is_surface_layer_ = is_surface_layer;
   if (cc_layer_) {
     if (is_surface_layer) {

third_party/blink/renderer/core/frame/remote_frame.h

@@ -81,13 +81,8 @@ class CORE_EXPORT RemoteFrame final : public Frame,
   void AddResourceTimingFromChild(
       mojom::blink::ResourceTimingInfoPtr timing) override;
 
-  void SetCcLayer(cc::Layer*,
-                  bool prevent_contents_opaque_changes,
-                  bool is_surface_layer);
+  void SetCcLayer(cc::Layer*, bool is_surface_layer);
   cc::Layer* GetCcLayer() const { return cc_layer_; }
-  bool WebLayerHasFixedContentsOpaque() const {
-    return prevent_contents_opaque_changes_;
-  }
 
   void AdvanceFocus(mojom::blink::FocusType, LocalFrame* source);
 
@@ -218,7 +213,6 @@ class CORE_EXPORT RemoteFrame final : public Frame,
   Member<RemoteFrameView> view_;
   RemoteSecurityContext security_context_;
   cc::Layer* cc_layer_ = nullptr;
-  bool prevent_contents_opaque_changes_ = false;
   bool is_surface_layer_ = false;
   ParsedFeaturePolicy feature_policy_header_;
   String unique_name_;

third_party/blink/renderer/core/frame/web_remote_frame_impl.cc

@@ -252,10 +252,8 @@ WebRemoteFrame* WebRemoteFrameImpl::CreateRemoteChild(
 }
 
 void WebRemoteFrameImpl::SetCcLayer(cc::Layer* layer,
-                                    bool prevent_contents_opaque_changes,
                                     bool is_surface_layer) {
-  GetFrame()->SetCcLayer(layer, prevent_contents_opaque_changes,
-                         is_surface_layer);
+  GetFrame()->SetCcLayer(layer, is_surface_layer);
 }
 
 void WebRemoteFrameImpl::SetCoreFrame(RemoteFrame* frame) {

third_party/blink/renderer/core/frame/web_remote_frame_impl.h

@@ -82,9 +82,7 @@ class CORE_EXPORT WebRemoteFrameImpl final
                                     AssociatedInterfaceProvider*,
                                     const base::UnguessableToken& frame_token,
                                     WebFrame* opener) override;
-  void SetCcLayer(cc::Layer*,
-                  bool prevent_contents_opaque_changes,
-                  bool is_surface_layer) override;
+  void SetCcLayer(cc::Layer*, bool is_surface_layer) override;
   void SetReplicatedOrigin(
       const WebSecurityOrigin&,
       bool is_potentially_trustworthy_opaque_origin) override;

third_party/blink/renderer/core/paint/compositing/composited_layer_mapping.cc

@@ -409,8 +409,7 @@ bool CompositedLayerMapping::UpdateGraphicsLayerConfiguration(
     } else if (auto* frame_owner =
                    DynamicTo<HTMLFrameOwnerElement>(layout_object.GetNode())) {
       if (auto* remote = DynamicTo<RemoteFrame>(frame_owner->ContentFrame())) {
-        graphics_layer_->SetContentsToCcLayer(
-            remote->GetCcLayer(), remote->WebLayerHasFixedContentsOpaque());
+        graphics_layer_->SetContentsToCcLayer(remote->GetCcLayer(), true);
       }
     }
   } else if (IsA<LayoutVideo>(layout_object)) {