From 1c5f34a179a33fd6be267963fc2895cf7138853c Mon Sep 17 00:00:00 2001
From: Brad Werth <bwerth@mozilla.com>
Date: Wed, 23 Mar 2022 15:24:38 +0000
Subject: [PATCH] Bug 1751217 Part 2: Change nsDeviceContext::GetDepth to
 eliminate the outparam. r=emilio

This function always succeeds so there's no reason to maintain an nsresult.

Differential Revision: https://phabricator.services.mozilla.com/D141407
---
 dom/base/nsScreen.cpp            | 4 +---
 gfx/src/nsDeviceContext.cpp      | 8 ++++----
 gfx/src/nsDeviceContext.h        | 2 +-
 layout/style/nsMediaFeatures.cpp | 2 +-
 4 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/dom/base/nsScreen.cpp b/dom/base/nsScreen.cpp
index 6f53f405a4c8..245b06f7c519 100644
--- a/dom/base/nsScreen.cpp
+++ b/dom/base/nsScreen.cpp
@@ -63,9 +63,7 @@ int32_t nsScreen::GetPixelDepth(ErrorResult& aRv) {
     return -1;
   }
 
-  uint32_t depth;
-  context->GetDepth(depth);
-  return depth;
+  return context->GetDepth();
 }
 
 nsPIDOMWindowOuter* nsScreen::GetOuter() const {
diff --git a/gfx/src/nsDeviceContext.cpp b/gfx/src/nsDeviceContext.cpp
index 2676320cf66c..1d1085e03964 100644
--- a/gfx/src/nsDeviceContext.cpp
+++ b/gfx/src/nsDeviceContext.cpp
@@ -211,7 +211,7 @@ already_AddRefed<gfxContext> nsDeviceContext::CreateRenderingContextCommon(
   return pContext.forget();
 }
 
-nsresult nsDeviceContext::GetDepth(uint32_t& aDepth) {
+uint32_t nsDeviceContext::GetDepth() {
   nsCOMPtr<nsIScreen> screen;
   FindScreen(getter_AddRefs(screen));
   if (!screen) {
@@ -219,9 +219,9 @@ nsresult nsDeviceContext::GetDepth(uint32_t& aDepth) {
     screenManager.GetPrimaryScreen(getter_AddRefs(screen));
     MOZ_ASSERT(screen);
   }
-  screen->GetColorDepth(reinterpret_cast<int32_t*>(&aDepth));
-
-  return NS_OK;
+  int32_t depth = 0;
+  screen->GetColorDepth(&depth);
+  return uint32_t(depth);
 }
 
 nsresult nsDeviceContext::GetDeviceSurfaceDimensions(nscoord& aWidth,
diff --git a/gfx/src/nsDeviceContext.h b/gfx/src/nsDeviceContext.h
index f64512a8983e..9fc795b5bf49 100644
--- a/gfx/src/nsDeviceContext.h
+++ b/gfx/src/nsDeviceContext.h
@@ -110,7 +110,7 @@ class nsDeviceContext final {
   /**
    * Return the bit depth of the device.
    */
-  nsresult GetDepth(uint32_t& aDepth);
+  uint32_t GetDepth();
 
   /**
    * Get the size of the displayable area of the output device
diff --git a/layout/style/nsMediaFeatures.cpp b/layout/style/nsMediaFeatures.cpp
index 25a6d8034311..dbb576754725 100644
--- a/layout/style/nsMediaFeatures.cpp
+++ b/layout/style/nsMediaFeatures.cpp
@@ -157,7 +157,7 @@ uint32_t Gecko_MediaFeatures_GetColorDepth(const Document* aDocument) {
 
   if (!nsContentUtils::ShouldResistFingerprinting(aDocument)) {
     if (nsDeviceContext* dx = GetDeviceContextFor(aDocument)) {
-      dx->GetDepth(depth);
+      depth = dx->GetDepth();
     }
   }