Invalidate scrollbars when window activity changes if needed

third_party/WebKit/Source/platform/scroll/Scrollbar.cpp

Index: third_party/WebKit/Source/platform/scroll/Scrollbar.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/Scrollbar.cpp b/third_party/WebKit/Source/platform/scroll/Scrollbar.cpp
index 469b6394d93039316d13b0c77627a23340e1f873..93f924051cc83c4dcd970604bb3372a3128b312f 100644
--- a/third_party/WebKit/Source/platform/scroll/Scrollbar.cpp
+++ b/third_party/WebKit/Source/platform/scroll/Scrollbar.cpp
@@ -30,6 +30,11 @@
 #include "platform/PlatformGestureEvent.h"
 #include "platform/PlatformMouseEvent.h"
 #include "platform/graphics/paint/CullRect.h"
+// See windowActiveChangedForSnowLeopardOnly() below.
+// TODO(ellyjones): remove this when Snow Leopard support is gone.
+#if OS(MACOSX)
+#include "platform/mac/VersionUtilMac.h"
+#endif
 #include "platform/scroll/ScrollAnimatorBase.h"
 #include "platform/scroll/ScrollableArea.h"
 #include "platform/scroll/ScrollbarTheme.h"
@@ -493,6 +498,21 @@ bool Scrollbar::shouldParticipateInHitTesting()
     return m_scrollableArea->scrollAnimator()->shouldScrollbarParticipateInHitTesting(this);
 }
 
+// Don't use this method. It will be removed later.
+// TODO(ellyjones): remove this method after Snow Leopard support drops.
+void Scrollbar::windowActiveChangedForSnowLeopardOnly()
+{
+#if OS(MACOSX)
+    // On Snow Leopard, scrollbars need to be invalidated when the window
+    // activity changes so that they take on the "inactive" scrollbar
+    // appearance. Later OS X releases do not have such an appearance.
+    if (m_theme && m_theme->invalidateOnWindowActiveChange()) {
+        ASSERT(IsOSSnowLeopard());
+        invalidate();
+    }
+#endif
+}
+
 bool Scrollbar::isWindowActive() const
 {
     return m_scrollableArea && m_scrollableArea->isActive();