Reland Change minimum length of Aura overlay scrollbars.

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

Index: third_party/WebKit/Source/platform/scroll/ScrollbarThemeOverlay.cpp
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollbarThemeOverlay.cpp b/third_party/WebKit/Source/platform/scroll/ScrollbarThemeOverlay.cpp
index 30ba2b9554699d95115ee07d6d3ed8f1506b2dd7..4b48e421ff6bf0343446524248152535051fe6bd 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollbarThemeOverlay.cpp
+++ b/third_party/WebKit/Source/platform/scroll/ScrollbarThemeOverlay.cpp
@@ -270,4 +270,19 @@ IntRect ScrollbarThemeOverlay::ninePatchThumbAperture(
   return Platform::current()->themeEngine()->ninePatchAperture(part);
 }
 
+int ScrollbarThemeOverlay::minimumThumbLength(
+    const ScrollbarThemeClient& scrollbar) {
+  if (scrollbar.orientation() == VerticalScrollbar) {
+    return Platform::current()
+        ->themeEngine()
+        ->getSize(WebThemeEngine::PartScrollbarVerticalThumb)
+        .height;
+  }
+
+  return Platform::current()
+      ->themeEngine()
+      ->getSize(WebThemeEngine::PartScrollbarHorizontalThumb)
+      .width;
+}
+
 }  // namespace blink