VR: Remove unnecessary transparency support from VR compositor.

chrome/browser/android/vr_shell/vr_compositor.cc

 // Copyright 2016 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 "chrome/browser/android/vr_shell/vr_compositor.h"
 
 #include <utility>
 
 #include "cc/layers/layer.h"
 #include "cc/layers/solid_color_layer.h"
 #include "content/public/browser/android/compositor.h"
 #include "content/public/browser/web_contents.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/android/window_android.h"
 
 namespace vr_shell {
 
-VrCompositor::VrCompositor(ui::WindowAndroid* window, bool transparent)
-    : background_color_(SK_ColorWHITE), transparent_(transparent) {
+VrCompositor::VrCompositor(ui::WindowAndroid* window) {
   compositor_.reset(content::Compositor::Create(this, window));
-  compositor_->SetHasTransparentBackground(transparent);
 }
 
 VrCompositor::~VrCompositor() {
   RestoreLayer();
 }
 
 void VrCompositor::SetLayer(content::WebContents* web_contents) {
   RestoreLayer();
   if (!web_contents) {
     scoped_refptr<cc::SolidColorLayer> layer = cc::SolidColorLayer::Create();
     layer->SetBackgroundColor(SK_ColorTRANSPARENT);
     compositor_->SetRootLayer(std::move(layer));
     return;
   }
   ui::ViewAndroid* view_android = web_contents->GetNativeView();
 
   // When we pass the layer for the ContentViewCore to the compositor it may be
   // removing it from its previous parent, so we remember that and restore it to
   // its previous parent on teardown.
   layer_ = view_android->GetLayer();
-
-  // Remember the old background color to be restored later.
-  background_color_ = layer_->background_color();
-  if (transparent_) {
-    layer_->SetBackgroundColor(SK_ColorTRANSPARENT);
-  }
   layer_parent_ = layer_->parent();
   compositor_->SetRootLayer(layer_);
 }
 
 void VrCompositor::RestoreLayer() {
-  if (!layer_)
-    return;
-  layer_->SetBackgroundColor(background_color_);
-  if (layer_parent_) {
+  if (layer_ && layer_parent_)
     layer_parent_->AddChild(layer_);
-  }
   layer_ = nullptr;
+  layer_parent_ = nullptr;
 }
 
 void VrCompositor::SurfaceDestroyed() {
   compositor_->SetSurface(nullptr);
 }
 
 void VrCompositor::SetWindowBounds(gfx::Size size) {
   compositor_->SetWindowBounds(size);
 }
 
 void VrCompositor::SurfaceChanged(jobject surface) {
   compositor_->SetSurface(surface);
 }
 
 }  // namespace vr_shell