--- a/layout/generic/nsFrame.cpp
+++ b/layout/generic/nsFrame.cpp
@@ -2179,34 +2179,61 @@ public:
                                mozilla::wr::IpcResourceUpdateQueue& aResources,
                                const StackingContextHelper& aSc,
                                mozilla::layers::WebRenderLayerManager* aManager,
                                nsDisplayListBuilder* aDisplayListBuilder) override;
   NS_DISPLAY_DECL_NAME("SelectionOverlay", TYPE_SELECTION_OVERLAY)
 private:
   Color ComputeColor() const;
 
+  static Color ComputeColorFromSelectionStyle(ComputedStyle&);
+  static Color ApplyTransparencyIfNecessary(nscolor);
+
   int16_t mSelectionValue;
 };
 
 Color
+nsDisplaySelectionOverlay::ApplyTransparencyIfNecessary(nscolor aColor)
+{
+  // If it has already alpha, leave it like that.
+  if (NS_GET_A(aColor) != 255) {
+    return ToDeviceColor(aColor);
+  }
+
+  // NOTE(emilio): Blink and WebKit do something slightly different here, and
+  // blend the color with white instead, both for overlays and text backgrounds.
+  auto color = Color::FromABGR(aColor);
+  color.a = 0.5;
+  return ToDeviceColor(color);
+}
+
+Color
+nsDisplaySelectionOverlay::ComputeColorFromSelectionStyle(ComputedStyle& aStyle)
+{
+  return ApplyTransparencyIfNecessary(
+    aStyle.GetVisitedDependentColor(&nsStyleBackground::mBackgroundColor));
+}
+
+Color
 nsDisplaySelectionOverlay::ComputeColor() const
 {
   LookAndFeel::ColorID colorID;
   if (mSelectionValue == nsISelectionController::SELECTION_ON) {
+    if (RefPtr<ComputedStyle> style = mFrame->ComputeSelectionStyle()) {
+      return ComputeColorFromSelectionStyle(*style);
+    }
     colorID = LookAndFeel::eColorID_TextSelectBackground;
   } else if (mSelectionValue == nsISelectionController::SELECTION_ATTENTION) {
     colorID = LookAndFeel::eColorID_TextSelectBackgroundAttention;
   } else {
     colorID = LookAndFeel::eColorID_TextSelectBackgroundDisabled;
   }
 
-  Color c = Color::FromABGR(LookAndFeel::GetColor(colorID, NS_RGB(255, 255, 255)));
-  c.a = .5;
-  return ToDeviceColor(c);
+  return ApplyTransparencyIfNecessary(
+    LookAndFeel::GetColor(colorID, NS_RGB(255, 255, 255)));
 }
 
 void nsDisplaySelectionOverlay::Paint(nsDisplayListBuilder* aBuilder,
                                       gfxContext* aCtx)
 {
   DrawTarget& aDrawTarget = *aCtx->GetDrawTarget();
   ColorPattern color(ComputeColor());
 
@@ -2229,55 +2256,78 @@ nsDisplaySelectionOverlay::CreateWebRend
   wr::LayoutRect bounds = aSc.ToRelativeLayoutRect(
     LayoutDeviceRect::FromAppUnits(nsRect(ToReferenceFrame(), Frame()->GetSize()),
                                    mFrame->PresContext()->AppUnitsPerDevPixel()));
   aBuilder.PushRect(bounds, bounds, !BackfaceIsHidden(),
                     wr::ToColorF(ComputeColor()));
   return true;
 }
 
+static Element*
+FindElementAncestorForMozSelection(nsIContent* aContent)
+{
+  NS_ENSURE_TRUE(aContent, nullptr);
+  while (aContent && aContent->IsInNativeAnonymousSubtree()) {
+    aContent = aContent->GetBindingParent();
+  }
+  NS_ASSERTION(aContent, "aContent isn't in non-anonymous tree?");
+  while (aContent && !aContent->IsElement()) {
+    aContent = aContent->GetParent();
+  }
+  return aContent ? aContent->AsElement() : nullptr;
+}
+
+
+already_AddRefed<ComputedStyle>
+nsIFrame::ComputeSelectionStyle() const
+{
+  Element* element = FindElementAncestorForMozSelection(GetContent());
+  RefPtr<ComputedStyle> sc =
+    PresContext()->StyleSet()->ProbePseudoElementStyle(
+      element, CSSPseudoElementType::selection, Style());
+  return sc.forget();
+}
+
 /********************************************************
 * Refreshes each content's frame
 *********************************************************/
 
 void
 nsFrame::DisplaySelectionOverlay(nsDisplayListBuilder*   aBuilder,
                                  nsDisplayList*          aList,
                                  uint16_t                aContentType)
 {
-  if (!IsSelected() || !IsVisibleForPainting(aBuilder))
+  if (!IsSelected() || !IsVisibleForPainting(aBuilder)) {
     return;
-
-  nsPresContext* presContext = PresContext();
-  nsIPresShell *shell = presContext->PresShell();
-  if (!shell)
+  }
+
+  int16_t displaySelection = PresShell()->GetSelectionFlags();
+  if (!(displaySelection & aContentType)) {
     return;
-
-  int16_t displaySelection = shell->GetSelectionFlags();
-  if (!(displaySelection & aContentType))
-    return;
+  }
 
   const nsFrameSelection* frameSelection = GetConstFrameSelection();
   int16_t selectionValue = frameSelection->GetDisplaySelection();
 
-  if (selectionValue <= nsISelectionController::SELECTION_HIDDEN)
+  if (selectionValue <= nsISelectionController::SELECTION_HIDDEN) {
     return; // selection is hidden or off
-
-  nsIContent *newContent = mContent->GetParent();
+  }
+
+  nsIContent* newContent = mContent->GetParent();
 
   //check to see if we are anonymous content
   int32_t offset = 0;
   if (newContent) {
     // XXXbz there has GOT to be a better way of determining this!
     offset = newContent->ComputeIndexOf(mContent);
   }
 
   //look up to see what selection(s) are on this frame
-  UniquePtr<SelectionDetails> details
-    = frameSelection->LookUpSelection(newContent, offset, 1, false);
+  UniquePtr<SelectionDetails> details =
+    frameSelection->LookUpSelection(newContent, offset, 1, false);
   if (!details)
     return;
 
   bool normal = false;
   for (SelectionDetails* sd = details.get(); sd; sd = sd->mNext.get()) {
     if (sd->mSelectionType == SelectionType::eNormal) {
       normal = true;
     }

--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -868,16 +868,18 @@ public:
    * The indicies must be consecutive and implementations MUST return null if
    * asked for an index that is out of range.
    */
   virtual ComputedStyle* GetAdditionalComputedStyle(int32_t aIndex) const = 0;
 
   virtual void SetAdditionalComputedStyle(int32_t aIndex,
                                           ComputedStyle* aComputedStyle) = 0;
 
+  already_AddRefed<ComputedStyle> ComputeSelectionStyle() const;
+
   /**
    * Accessor functions for geometric parent.
    */
   nsContainerFrame* GetParent() const { return mParent; }
 
   /**
    * Gets the parent of a frame, using the parent of the placeholder for
    * out-of-flow frames.

--- a/layout/generic/nsImageFrame.cpp
+++ b/layout/generic/nsImageFrame.cpp
@@ -1894,24 +1894,20 @@ nsImageFrame::ShouldDisplaySelection()
 {
   nsPresContext* presContext = PresContext();
   int16_t displaySelection = presContext->PresShell()->GetSelectionFlags();
   if (!(displaySelection & nsISelectionDisplay::DISPLAY_IMAGES))
     return false;//no need to check the blue border, we cannot be drawn selected
 
   // If the image is the only selected node, don't draw the selection overlay.
   // This can happen when selecting an image in contenteditable context.
-  if (displaySelection == nsISelectionDisplay::DISPLAY_ALL)
-  {
-    const nsFrameSelection* frameSelection = GetConstFrameSelection();
-    if (frameSelection)
-    {
+  if (displaySelection == nsISelectionDisplay::DISPLAY_ALL) {
+    if (const nsFrameSelection* frameSelection = GetConstFrameSelection()) {
       const Selection* selection = frameSelection->GetSelection(SelectionType::eNormal);
-      if (selection && selection->RangeCount() == 1)
-      {
+      if (selection && selection->RangeCount() == 1) {
         nsINode* parent = mContent->GetParent();
         int32_t thisOffset = parent->ComputeIndexOf(mContent);
         nsRange* range = selection->GetRangeAt(0);
         if (range->GetStartContainer() == parent &&
             range->GetEndContainer() == parent &&
             static_cast<int32_t>(range->StartOffset()) == thisOffset &&
             static_cast<int32_t>(range->EndOffset()) == thisOffset + 1) {
           return false;

--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@@ -4052,30 +4052,16 @@ nsTextPaintStyle::GetSystemFieldForegrou
 
 nscolor
 nsTextPaintStyle::GetSystemFieldBackgroundColor()
 {
   InitCommonColors();
   return mSystemFieldBackgroundColor;
 }
 
-static Element*
-FindElementAncestorForMozSelection(nsIContent* aContent)
-{
-  NS_ENSURE_TRUE(aContent, nullptr);
-  while (aContent && aContent->IsInNativeAnonymousSubtree()) {
-    aContent = aContent->GetBindingParent();
-  }
-  NS_ASSERTION(aContent, "aContent isn't in non-anonymous tree?");
-  while (aContent && !aContent->IsElement()) {
-    aContent = aContent->GetParent();
-  }
-  return aContent ? aContent->AsElement() : nullptr;
-}
-
 bool
 nsTextPaintStyle::InitSelectionColorsAndShadow()
 {
   if (mInitSelectionColorsAndShadow)
     return true;
 
   int16_t selectionFlags;
   int16_t selectionStatus = mFrame->GetSelectionStatus(&selectionFlags);
@@ -4084,35 +4070,25 @@ nsTextPaintStyle::InitSelectionColorsAnd
     // Not displaying the normal selection.
     // We're not caching this fact, so every call to GetSelectionColors
     // will come through here. We could avoid this, but it's not really worth it.
     return false;
   }
 
   mInitSelectionColorsAndShadow = true;
 
-  nsIFrame* nonGeneratedAncestor = nsLayoutUtils::GetNonGeneratedAncestor(mFrame);
-  Element* selectionElement =
-    FindElementAncestorForMozSelection(nonGeneratedAncestor->GetContent());
-
-  if (selectionElement &&
-      selectionStatus == nsISelectionController::SELECTION_ON) {
-    RefPtr<ComputedStyle> sc =
-      mPresContext->StyleSet()->
-        ProbePseudoElementStyle(selectionElement,
-                                CSSPseudoElementType::selection,
-                                mFrame->Style());
-    // Use -moz-selection pseudo class.
-    if (sc) {
+  if (selectionStatus == nsISelectionController::SELECTION_ON) {
+    // Use ::selection pseudo class.
+    if (RefPtr<ComputedStyle> style = mFrame->ComputeSelectionStyle()) {
       mSelectionBGColor =
-        sc->GetVisitedDependentColor(&nsStyleBackground::mBackgroundColor);
+        style->GetVisitedDependentColor(&nsStyleBackground::mBackgroundColor);
       mSelectionTextColor =
-        sc->GetVisitedDependentColor(&nsStyleText::mWebkitTextFillColor);
+        style->GetVisitedDependentColor(&nsStyleText::mWebkitTextFillColor);
       mHasSelectionShadow = true;
-      mSelectionShadow = sc->StyleText()->mTextShadow;
+      mSelectionShadow = style->StyleText()->mTextShadow;
       return true;
     }
   }
 
   nscolor selectionBGColor =
     LookAndFeel::GetColor(LookAndFeel::eColorID_TextSelectBackground);
 
   if (selectionStatus == nsISelectionController::SELECTION_ATTENTION) {

--- a/testing/web-platform/meta/MANIFEST.json
+++ b/testing/web-platform/meta/MANIFEST.json
@@ -160624,16 +160624,40 @@
       [
        "/css/reference/ref-filled-green-100px-square.xht",
        "=="
       ]
      ],
      {}
     ]
    ],
+   "css/selectors/selection-image-001.html": [
+    [
+     "/css/selectors/selection-image-001.html",
+     [
+      [
+       "/css/selectors/selection-image-001-noref.html",
+       "!="
+      ]
+     ],
+     {}
+    ]
+   ],
+   "css/selectors/selection-image-002.html": [
+    [
+     "/css/selectors/selection-image-002.html",
+     [
+      [
+       "/css/selectors/selection-image-001-no-selection-noref.html",
+       "!="
+      ]
+     ],
+     {}
+    ]
+   ],
    "css/selectors/selector-placeholder-shown-type-change-001.html": [
     [
      "/css/selectors/selector-placeholder-shown-type-change-001.html",
      [
       [
        "/css/selectors/selector-placeholder-shown-type-change-001-ref.html",
        "=="
       ]
@@ -262149,16 +262173,21 @@
      {}
     ]
    ],
    "css/selectors/of-type-selectors-ref.xhtml": [
     [
      {}
     ]
    ],
+   "css/selectors/resources/blue15x15.png": [
+    [
+     {}
+    ]
+   ],
    "css/selectors/selector-placeholder-shown-type-change-001-ref.html": [
     [
      {}
     ]
    ],
    "css/selectors/selector-placeholder-shown-type-change-002-ref.html": [
     [
      {}
@@ -385648,16 +385677,28 @@
      {}
     ]
    ],
    "css/mediaqueries/media-queries-003.xht": [
     [
      "/css/mediaqueries/media-queries-003.xht",
      {}
     ]
+   ],
+   "css/selectors/selection-image-001-no-selection-noref.html": [
+    [
+     "/css/selectors/selection-image-001-no-selection-noref.html",
+     {}
+    ]
+   ],
+   "css/selectors/selection-image-001-noref.html": [
+    [
+     "/css/selectors/selection-image-001-noref.html",
+     {}
+    ]
    ]
   },
   "wdspec": {
    "webdriver/tests/actions/key.py": [
     [
      "/webdriver/tests/actions/key.py",
      {}
     ]
@@ -529060,24 +529101,44 @@
   "css/selectors/of-type-selectors-ref.xhtml": [
    "59f848418882c75898c422a9600c14ffab64c3d9",
    "support"
   ],
   "css/selectors/of-type-selectors.xhtml": [
    "607553f41a33ce3630752cdf027c9f904833a19d",
    "reftest"
   ],
+  "css/selectors/resources/blue15x15.png": [
+   "eb48032c07bfeb1d3b6be6e5c9c34d2fe2180767",
+   "support"
+  ],
   "css/selectors/root-siblings.htm": [
    "0d6e67589dab95d5362f82a99565947ebb487658",
    "reftest"
   ],
   "css/selectors/scope-without-scoping.html": [
    "f70b8d60543c5a28fcf955b1780f15c03d60991a",
    "reftest"
   ],
+  "css/selectors/selection-image-001-no-selection-noref.html": [
+   "b9a627630a8dcfaa70c74fc11ac9635aa00ac32c",
+   "visual"
+  ],
+  "css/selectors/selection-image-001-noref.html": [
+   "add1c00be4957ffef599aee52d061be7c09607bc",
+   "visual"
+  ],
+  "css/selectors/selection-image-001.html": [
+   "134b946744b45f488470dc5d1c690ee9a4855cbb",
+   "reftest"
+  ],
+  "css/selectors/selection-image-002.html": [
+   "5e2d33709b654a1f66eedcff995c8a3e9a8e01c5",
+   "reftest"
+  ],
   "css/selectors/selector-placeholder-shown-type-change-001-ref.html": [
    "92303d06943581738f58ff5d342ef1336539f66a",
    "support"
   ],
   "css/selectors/selector-placeholder-shown-type-change-001.html": [
    "6d84d237fe4b6d7f01e6c7c6129bdc8ccb06cf90",
    "reftest"
   ],

--- a/testing/web-platform/mozilla/meta/MANIFEST.json
+++ b/testing/web-platform/mozilla/meta/MANIFEST.json
@@ -1424,17 +1424,17 @@
    "3b21a62dbc8379a202e8a0beda813c89f762ae2d",
    "support"
   ],
   "wasm/js/get_local.wast.js": [
    "332a192149e2cede2d9219432fd3c6085ac69f68",
    "support"
   ],
   "wasm/js/globals.wast.js": [
-   "86b3c907edd8bb3867c5a5aaaebf6066a215b154",
+   "1cb0dc48bd61564325053bf49ae7a1bdb27f5c49",
    "support"
   ],
   "wasm/js/harness/index.js": [
    "c1f8ca410de85f15e1d9e57748a2fb9f607be40f",
    "support"
   ],
   "wasm/js/harness/wasm-constants.js": [
    "6aba4f5fb4127cd56e1381bfb18204edde41abb2",

new file mode 100644
index 0000000000000000000000000000000000000000..89de32fdb8a4e48b1320f40f5a75352773077cee
GIT binary patch
literal 185
zc%17D@N?(olHy`uVBq!ia0vp^{2<K11SGd?VUh(>oCO|{#S9F5he4R}c>anMpde#$
zkh>GZx^prwfgF}}M_)$<hK>E)e-c@Ne1&9>AYTTCDm4a%h86~fUqGRT7Yq!g1`G_Z
z5*Qe)W-u^_7tGleXakf`@^o<w(FjgXN%(Qzfs0|4n%u+%B2Ty;@ydnvnyztk0=k6z
V)g}Gv*iewk44$rjF6*2UngFS5E#&|J

new file mode 100644
--- /dev/null
+++ b/testing/web-platform/tests/css/selectors/selection-image-001-no-selection-noref.html
@@ -0,0 +1,7 @@
+<!doctype html>
+<title>CSS Test Reference</title>
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1449010">
+<p>
+  Some text <img src="resources/blue15x15.png"> some more.
+</p>

new file mode 100644
--- /dev/null
+++ b/testing/web-platform/tests/css/selectors/selection-image-001-noref.html
@@ -0,0 +1,15 @@
+<!doctype html>
+<title>CSS Test Reference</title>
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1449010">
+<p>
+  Some text <img src="resources/blue15x15.png"> some more.
+</p>
+<script>
+onload = () => {
+  getSelection().removeAllRanges();
+  let r = document.createRange();
+  r.selectNode(document.documentElement);
+  getSelection().addRange(r);
+}
+</script>

new file mode 100644
--- /dev/null
+++ b/testing/web-platform/tests/css/selectors/selection-image-001.html
@@ -0,0 +1,21 @@
+<!doctype html>
+<title>::selection is respected on images</title>
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1449010">
+<link rel="mismatch" href="selection-image-001-noref.html">
+<style>
+img::selection {
+  background: green;
+}
+</style>
+<p>
+  Some text <img src="resources/blue15x15.png"> some more.
+</p>
+<script>
+onload = () => {
+  getSelection().removeAllRanges();
+  let r = document.createRange();
+  r.selectNode(document.documentElement);
+  getSelection().addRange(r);
+}
+</script>

new file mode 100644
--- /dev/null
+++ b/testing/web-platform/tests/css/selectors/selection-image-002.html
@@ -0,0 +1,16 @@
+<!doctype html>
+<title>CSS Test: Image and text selection is painted.</title>
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1449010">
+<link rel="mismatch" href="selection-image-001-no-selection-noref.html">
+<p>
+  Some text <img src="resources/blue15x15.png"> some more.
+</p>
+<script>
+onload = () => {
+  getSelection().removeAllRanges();
+  let r = document.createRange();
+  r.selectNode(document.documentElement);
+  getSelection().addRange(r);
+}
+</script>