Removing GraphicsContext from ImageBuffer

Source/platform/scroll/ScrollbarThemeMacNonOverlayAPI.mm

Index: Source/platform/scroll/ScrollbarThemeMacNonOverlayAPI.mm
diff --git a/Source/platform/scroll/ScrollbarThemeMacNonOverlayAPI.mm b/Source/platform/scroll/ScrollbarThemeMacNonOverlayAPI.mm
index 249775a40b0bc6481cd35d5748c23f353f0cdc38..f344e339e0f3fb9249c5022fbc852f0464ac3c1e 100644
--- a/Source/platform/scroll/ScrollbarThemeMacNonOverlayAPI.mm
+++ b/Source/platform/scroll/ScrollbarThemeMacNonOverlayAPI.mm
@@ -114,8 +114,8 @@ bool ScrollbarThemeMacNonOverlayAPI::paint(ScrollbarThemeClient* scrollbar, Grap
 
     // The Aqua scrollbar is buggy when rotated and scaled.  We will just draw into a bitmap if we detect a scale or rotation.
     bool canDrawDirectly = currentCTM.a == 1.0f && currentCTM.b == 0.0f && currentCTM.c == 0.0f && (currentCTM.d == 1.0f || currentCTM.d == -1.0f);
-    GraphicsContext* drawingContext = context;
     OwnPtr<ImageBuffer> imageBuffer;
+    SkCanvas* drawingCanvas;
     if (!canDrawDirectly) {
         trackInfo.bounds = IntRect(IntPoint(), scrollbar->frameRect().size());
 
@@ -127,14 +127,16 @@ bool ScrollbarThemeMacNonOverlayAPI::paint(ScrollbarThemeClient* scrollbar, Grap
         if (!imageBuffer)
             return true;
 
-        drawingContext = imageBuffer->context();
+        drawingCanvas = imageBuffer->canvas();
+    } else {
+        drawingCanvas = canvas;
     }
 
     // Draw the track and its thumb.
     gfx::SkiaBitLocker bitLocker(
-        drawingContext->canvas(),
+        drawingCanvas,
         ThemeMac::inflateRectForAA(scrollbar->frameRect()),
-        drawingContext->deviceScaleFactor());
+        canDrawDirectly ? context->deviceScaleFactor() : 1.0f);
     CGContextRef cgContext = bitLocker.cgContext();
     HIThemeDrawTrack(&trackInfo, 0, cgContext, kHIThemeOrientationNormal);
 
@@ -148,7 +150,7 @@ bool ScrollbarThemeMacNonOverlayAPI::paint(ScrollbarThemeClient* scrollbar, Grap
     // Inset a bit.
     tickmarkTrackRect.setX(tickmarkTrackRect.x() + 2);
     tickmarkTrackRect.setWidth(tickmarkTrackRect.width() - 5);
-    paintGivenTickmarks(drawingContext, scrollbar, tickmarkTrackRect, tickmarks);
+    paintGivenTickmarks(drawingCanvas, scrollbar, tickmarkTrackRect, tickmarks);
 
     if (!canDrawDirectly) {
         ASSERT(imageBuffer);