diff --git a/chromium/third_party/WebKit/Source/core/rendering/RenderThemeChromiumMac.mm b/chromium/third_party/WebKit/Source/core/rendering/RenderThemeChromiumMac.mm
index a25be5a7c8955e840668895f9460d075343f76eb..bcc29886eb73c6c088aa60060a2ea11bb846ad7f 100644
--- a/chromium/third_party/WebKit/Source/core/rendering/RenderThemeChromiumMac.mm
+++ b/chromium/third_party/WebKit/Source/core/rendering/RenderThemeChromiumMac.mm
@@ -1064,7 +1064,7 @@ bool RenderThemeChromiumMac::paintProgressBar(RenderObject* renderObject, const
         return true;
 
     float zoomLevel = renderObject->style()->effectiveZoom();
-    int controlSize = controlSizeForFont(renderObject->style());
+    NSControlSize controlSize = controlSizeForFont(renderObject->style());
     IntSize size = progressBarSizes()[controlSize];
     size.setHeight(size.height() * zoomLevel);
     size.setWidth(rect.width());
diff --git a/chromium/third_party/WebKit/Source/platform/mac/ScrollAnimatorMac.mm b/chromium/third_party/WebKit/Source/platform/mac/ScrollAnimatorMac.mm
index c5a33df09c5b289ee16456234226f4300965a318..e61a0b59ab29cf26bc1a5816ac062f5200eafaa7 100644
--- a/chromium/third_party/WebKit/Source/platform/mac/ScrollAnimatorMac.mm
+++ b/chromium/third_party/WebKit/Source/platform/mac/ScrollAnimatorMac.mm
@@ -603,7 +603,7 @@ ScrollAnimatorMac::ScrollAnimatorMac(ScrollableArea* scrollableArea)
     if (ScrollbarThemeMacCommon::isOverlayAPIAvailable()) {
         m_scrollbarPainterControllerDelegate.adoptNS([[WebScrollbarPainterControllerDelegate alloc] initWithScrollableArea:scrollableArea]);
         m_scrollbarPainterController = [[[NSClassFromString(@"NSScrollerImpPair") alloc] init] autorelease];
-        [m_scrollbarPainterController.get() setDelegate:m_scrollbarPainterControllerDelegate.get()];
+        [m_scrollbarPainterController setDelegate:(id)m_scrollbarPainterControllerDelegate.get()];
         [m_scrollbarPainterController.get() setScrollerStyle:ScrollbarThemeMacCommon::recommendedScrollerStyle()];
     }
 }
@@ -888,7 +888,7 @@ void ScrollAnimatorMac::didAddVerticalScrollbar(Scrollbar* scrollbar)
     ASSERT(!m_verticalScrollbarPainterDelegate);
     m_verticalScrollbarPainterDelegate.adoptNS([[WebScrollbarPainterDelegate alloc] initWithScrollbar:scrollbar]);
 
-    [painter setDelegate:m_verticalScrollbarPainterDelegate.get()];
+    [painter setDelegate:(id)m_verticalScrollbarPainterDelegate.get()];
     [m_scrollbarPainterController.get() setVerticalScrollerImp:painter];
     if (scrollableArea()->inLiveResize())
         [painter setKnobAlpha:1];
@@ -923,7 +923,7 @@ void ScrollAnimatorMac::didAddHorizontalScrollbar(Scrollbar* scrollbar)
     ASSERT(!m_horizontalScrollbarPainterDelegate);
     m_horizontalScrollbarPainterDelegate.adoptNS([[WebScrollbarPainterDelegate alloc] initWithScrollbar:scrollbar]);
 
-    [painter setDelegate:m_horizontalScrollbarPainterDelegate.get()];
+    [painter setDelegate:(id)m_horizontalScrollbarPainterDelegate.get()];
     [m_scrollbarPainterController.get() setHorizontalScrollerImp:painter];
     if (scrollableArea()->inLiveResize())
         [painter setKnobAlpha:1];
diff --git a/chromium/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm b/chromium/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm
index 05e4ccddfe7c267ba27cce8a45bc3534cbfffb96..51b9471d746f49453fe275ea5fb1b431107e2dfd 100644
--- a/chromium/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm
+++ b/chromium/third_party/WebKit/Source/platform/scroll/ScrollbarThemeMacOverlayAPI.mm
@@ -54,12 +54,25 @@ static bool supportsExpandedScrollbars()
     return globalSupportsExpandedScrollbars;
 }
 
+static NSControlSize scrollbarControlSizeToNSControlSize(ScrollbarControlSize controlSize)
+{
+    switch (controlSize) {
+    case RegularScrollbar:
+        return NSRegularControlSize;
+    case SmallScrollbar:
+        return NSSmallControlSize;
+    }
+
+    ASSERT_NOT_REACHED();
+    return NSRegularControlSize;
+}
+
 void ScrollbarThemeMacOverlayAPI::registerScrollbar(ScrollbarThemeClient* scrollbar)
 {
     ScrollbarThemeMacCommon::registerScrollbar(scrollbar);
 
     bool isHorizontal = scrollbar->orientation() == HorizontalScrollbar;
-    ScrollbarPainter scrollbarPainter = [NSClassFromString(@"NSScrollerImp") scrollerImpWithStyle:recommendedScrollerStyle() controlSize:(NSControlSize)scrollbar->controlSize() horizontal:isHorizontal replacingScrollerImp:nil];
+    ScrollbarPainter scrollbarPainter = [NSClassFromString(@"NSScrollerImp") scrollerImpWithStyle:recommendedScrollerStyle() controlSize:scrollbarControlSizeToNSControlSize(scrollbar->controlSize()) horizontal:isHorizontal replacingScrollerImp:nil];
     scrollbarPainterMap()->add(scrollbar, scrollbarPainter);
     updateEnabledState(scrollbar);
     updateScrollbarOverlayStyle(scrollbar);
@@ -122,7 +135,7 @@ void ScrollbarThemeMacOverlayAPI::paintThumb(GraphicsContext* context, Scrollbar
 
 int ScrollbarThemeMacOverlayAPI::scrollbarThickness(ScrollbarControlSize controlSize)
 {
-    ScrollbarPainter scrollbarPainter = [NSClassFromString(@"NSScrollerImp") scrollerImpWithStyle:recommendedScrollerStyle() controlSize:controlSize horizontal:NO replacingScrollerImp:nil];
+    ScrollbarPainter scrollbarPainter = [NSClassFromString(@"NSScrollerImp") scrollerImpWithStyle:recommendedScrollerStyle() controlSize:scrollbarControlSizeToNSControlSize(controlSize) horizontal:NO replacingScrollerImp:nil];
     if (supportsExpandedScrollbars())
         [scrollbarPainter setExpanded:YES];
     return [scrollbarPainter trackBoxWidth];
diff --git a/chromium/third_party/WebKit/Source/web/mac/WebScrollbarTheme.mm b/chromium/third_party/WebKit/Source/web/mac/WebScrollbarTheme.mm
index 95cc080f9d5118a7e86ee5d8a2ae013d389a7d97..9b06dc14c10d836c2a7c2fda9ff989416eae8a66 100644
--- a/chromium/third_party/WebKit/Source/web/mac/WebScrollbarTheme.mm
+++ b/chromium/third_party/WebKit/Source/web/mac/WebScrollbarTheme.mm
@@ -40,8 +40,8 @@ using namespace WebCore;
 
 namespace blink {
 
-COMPILE_ASSERT(ScrollerStyleLegacy == NSScrollerStyleLegacy, ScrollerStyle_Legacy_must_be_equal);
-COMPILE_ASSERT(ScrollerStyleOverlay == NSScrollerStyleOverlay, ScrollerStyle_Overlay_must_be_equal);
+COMPILE_ASSERT(static_cast<NSScrollerStyle>(ScrollerStyleLegacy) == NSScrollerStyleLegacy, ScrollerStyle_Legacy_must_be_equal);
+COMPILE_ASSERT(static_cast<NSScrollerStyle>(ScrollerStyleOverlay) == NSScrollerStyleOverlay, ScrollerStyle_Overlay_must_be_equal);
 
 void WebScrollbarTheme::updateScrollbars(
     float initialButtonDelay, float autoscrollButtonDelay,
@@ -52,7 +52,7 @@ void WebScrollbarTheme::updateScrollbars(
         return;
 
     static_cast<ScrollbarThemeMacCommon*>(ScrollbarTheme::theme())->preferencesChanged(
-        initialButtonDelay, autoscrollButtonDelay, preferredScrollerStyle, redraw);
+        initialButtonDelay, autoscrollButtonDelay, static_cast<NSScrollerStyle>(preferredScrollerStyle), redraw);
 }
 
 } // namespace blink