Aura overlay scrollbars adjust color for dark backgrounds

content/child/webthemeengine_impl_default.cc

Index: content/child/webthemeengine_impl_default.cc
diff --git a/content/child/webthemeengine_impl_default.cc b/content/child/webthemeengine_impl_default.cc
index 7fa4ba7d6497c2d374257db255e91d283d2c24cc..f1e56ba56e90c7890a0033fe0eb0382ad597942c 100644
--- a/content/child/webthemeengine_impl_default.cc
+++ b/content/child/webthemeengine_impl_default.cc
@@ -8,12 +8,12 @@
 #include "skia/ext/platform_canvas.h"
 #include "third_party/WebKit/public/platform/WebRect.h"
 #include "third_party/WebKit/public/platform/WebSize.h"
-#include "ui/native_theme/native_theme.h"
 
 using blink::WebCanvas;
 using blink::WebColor;
 using blink::WebRect;
 using blink::WebThemeEngine;
+using blink::WebScrollbarOverlayColorTheme;
 
 namespace content {
 namespace {
@@ -78,6 +78,20 @@ static ui::NativeTheme::Part NativeThemePart(
   }
 }
 
+static ui::NativeTheme::ScrollbarOverlayColorTheme
+NativeThemeScrollbarOverlayColorTheme(WebScrollbarOverlayColorTheme theme) {
+  switch (theme) {
+    case WebScrollbarOverlayColorTheme::WebScrollbarOverlayColorThemeDefault:
+      return ui::NativeTheme::ScrollbarOverlayColorThemeDefault;
+    case WebScrollbarOverlayColorTheme::WebScrollbarOverlayColorThemeLight:
+      return ui::NativeTheme::ScrollbarOverlayColorThemeLight;
+    case WebScrollbarOverlayColorTheme::WebScrollbarOverlayColorThemeDark:
+      return ui::NativeTheme::ScrollbarOverlayColorThemeDark;
+    default:
+      return ui::NativeTheme::ScrollbarOverlayColorThemeDefault;
+  }
+}
+
 static ui::NativeTheme::State NativeThemeState(
     WebThemeEngine::State state) {
   switch (state) {
@@ -177,6 +191,12 @@ static void GetNativeThemeExtraParams(
       native_theme_extra_params->progress_bar.value_rect_height =
           extra_params->progressBar.valueRectHeight;
       break;
+    case WebThemeEngine::PartScrollbarHorizontalThumb:
+    case WebThemeEngine::PartScrollbarVerticalThumb:
+      native_theme_extra_params->scrollbar_thumb.scrollbar_theme =
+          static_cast<ui::NativeTheme::ScrollbarOverlayColorTheme>(

[bokan, 2016/10/21 20:11:38]

use the NativeThemeScrollbarOverlayColorTheme function rather than casting.

+              extra_params->scrollbarThumb.scrollbarTheme);
+      break;
     default:
       break;  // Parts that have no extra params get here.
   }
@@ -221,15 +241,18 @@ void WebThemeEngineImpl::paint(
       native_theme_extra_params);
 }
 
-void WebThemeEngineImpl::paintStateTransition(blink::WebCanvas* canvas,
-                                              WebThemeEngine::Part part,
-                                              WebThemeEngine::State startState,
-                                              WebThemeEngine::State endState,
-                                              double progress,
-                                              const blink::WebRect& rect) {
+void WebThemeEngineImpl::paintStateTransition(
+    blink::WebCanvas* canvas,
+    WebThemeEngine::Part part,
+    WebThemeEngine::State startState,
+    WebThemeEngine::State endState,
+    double progress,
+    const blink::WebRect& rect,
+    WebScrollbarOverlayColorTheme theme) {
   ui::NativeTheme::GetInstanceForWeb()->PaintStateTransition(
       canvas, NativeThemePart(part), NativeThemeState(startState),
-      NativeThemeState(endState), progress, gfx::Rect(rect));
+      NativeThemeState(endState), progress, gfx::Rect(rect),
+      NativeThemeScrollbarOverlayColorTheme(theme));
 }
 
 #if defined(OS_WIN)