HDR: Do nonlinear blending in the compositor

cc/surfaces/display.cc

Index: cc/surfaces/display.cc
diff --git a/cc/surfaces/display.cc b/cc/surfaces/display.cc
index f56de857d78ead01255e991fec971896e91d9ae0..86e376915801bebd29fa02ba48f0854084683d20 100644
--- a/cc/surfaces/display.cc
+++ b/cc/surfaces/display.cc
@@ -159,10 +159,13 @@ void Display::Resize(const gfx::Size& size) {
     scheduler_->DisplayResized();
 }
 
-void Display::SetColorSpace(const gfx::ColorSpace& color_space) {
-  device_color_space_ = color_space;
-  if (aggregator_)
-    aggregator_->SetOutputColorSpace(device_color_space_);
+void Display::SetColorSpace(const gfx::ColorSpace& blending_color_space,
+                            const gfx::ColorSpace& device_color_space) {
+  blending_color_space_ = blending_color_space;
+  device_color_space_ = device_color_space;
+  if (aggregator_) {
+    aggregator_->SetOutputColorSpace(blending_color_space, device_color_space_);
+  }
 }
 
 void Display::SetOutputIsSecure(bool secure) {
@@ -219,7 +222,7 @@ void Display::InitializeRenderer() {
   aggregator_.reset(new SurfaceAggregator(
       surface_manager_, resource_provider_.get(), output_partial_list));
   aggregator_->set_output_is_secure(output_is_secure_);
-  aggregator_->SetOutputColorSpace(device_color_space_);
+  aggregator_->SetOutputColorSpace(blending_color_space_, device_color_space_);
 }
 
 void Display::UpdateRootSurfaceResourcesLocked() {