Remove code blocking forced colors on Mac

With CL:2587618, we no longer need to block forced colors mode from
affecting Mac in blink. The reason being that we are tracking forced
colors separately from high contrast in NativeTheme, so we don't need
to worry about increased contrast accidentally triggering forced colors
on Mac.

There is work underway to add a devtools emulation feature for Windows
high contrast to allow developers to test their webpages in forced
colors mode without a Windows device. This change will likely allow
for a proper emulation on Mac.

This CL should not result in any functional changes (other than the fact
that forcing high contrast will now affect Mac, which is why the forced
colors tests now pass on Mac, and various related web tests needed to
be rebaselined.)

Bug: 1107431
Change-Id: Ie3a3547c927587dd638a53f6307c69aca9d99779
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2591489
Commit-Queue: Alison Maher <almaher@microsoft.com>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Reviewed-by: Ionel Popescu <iopopesc@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#840195}

content/child/webthemeengine_impl_mac.cc

@@ -9,15 +9,6 @@
 
 namespace content {
 
-blink::ForcedColors WebThemeEngineMac::GetForcedColors() const {
-  return forced_colors_;
-}
-
-void WebThemeEngineMac::SetForcedColors(
-    const blink::ForcedColors forced_colors) {
-  forced_colors_ = forced_colors;
-}
-
 void WebThemeEngineMac::Paint(cc::PaintCanvas* canvas,
                               WebThemeEngine::Part part,
                               WebThemeEngine::State state,

content/child/webthemeengine_impl_mac.h

@@ -13,9 +13,6 @@ class WebThemeEngineMac : public WebThemeEngineDefault {
  public:
   ~WebThemeEngineMac() override {}
 
-  blink::ForcedColors GetForcedColors() const override;
-  void SetForcedColors(const blink::ForcedColors forced_colors) override;
-
   void Paint(cc::PaintCanvas* canvas,
              blink::WebThemeEngine::Part part,
              blink::WebThemeEngine::State state,
@@ -31,9 +28,6 @@ class WebThemeEngineMac : public WebThemeEngineDefault {
       const gfx::Rect& rect,
       const WebThemeEngine::ExtraParams* extra_params,
       blink::mojom::ColorScheme color_scheme);
-
- private:
-  blink::ForcedColors forced_colors_ = blink::ForcedColors::kNone;
 };
 
 }  // namespace content

third_party/blink/web_tests/TestExpectations

@@ -4986,14 +4986,7 @@ crbug.com/989717 [ Fuchsia ] http/tests/preload/avoid_delaying_onload_link_prelo
 # Expected failures for forced colors mode tests when the corresponding flags
 # are not enabled.
 crbug.com/970285 external/wpt/forced-colors-mode/* [ Failure ]
-
-# Virtual forced colors mode tests should fail on macOS since macOS high
-# contrast does not imply forced colors mode. The tests should pass on all other
-# platforms.
-crbug.com/970285 [ Mac ] virtual/forced-high-contrast-colors/* [ Failure ]
-crbug.com/970285 [ Win ] virtual/forced-high-contrast-colors/* [ Pass ]
-crbug.com/970285 [ Linux ] virtual/forced-high-contrast-colors/* [ Pass ]
-crbug.com/970285 [ Android ] virtual/forced-high-contrast-colors/* [ Pass ]
+crbug.com/970285 virtual/forced-high-contrast-colors/external/wpt/forced-colors-mode/* [ Pass ]
 
 # Expected failures for dark mode tests when the corresponding flags
 # are not enabled.