Reland Change minimum length of Aura overlay scrollbars.

content/child/webthemeengine_impl_android.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/child/webthemeengine_impl_android.h"
 
 #include "base/logging.h"
 #include "base/sys_info.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/WebKit/public/platform/WebRect.h"
@@ skipping 21 matching lines @@
   switch (part) {
     case WebThemeEngine::PartScrollbarDownArrow:
       return ui::NativeTheme::kScrollbarDownArrow;
     case WebThemeEngine::PartScrollbarLeftArrow:
       return ui::NativeTheme::kScrollbarLeftArrow;
     case WebThemeEngine::PartScrollbarRightArrow:
       return ui::NativeTheme::kScrollbarRightArrow;
     case WebThemeEngine::PartScrollbarUpArrow:
       return ui::NativeTheme::kScrollbarUpArrow;
     case WebThemeEngine::PartScrollbarHorizontalThumb:
+      return ui::NativeTheme::kScrollbarHorizontalThumb;
     case WebThemeEngine::PartScrollbarVerticalThumb:
+      return ui::NativeTheme::kScrollbarVerticalThumb;
     case WebThemeEngine::PartScrollbarHorizontalTrack:
+      return ui::NativeTheme::kScrollbarHorizontalTrack;
     case WebThemeEngine::PartScrollbarVerticalTrack:
+      return ui::NativeTheme::kScrollbarVerticalTrack;
     case WebThemeEngine::PartScrollbarCorner:
-      // Android doesn't draw scrollbars.
-      NOTREACHED();
-      return static_cast<ui::NativeTheme::Part>(0);
+      return ui::NativeTheme::kScrollbarCorner;
     case WebThemeEngine::PartCheckbox:
       return ui::NativeTheme::kCheckbox;
     case WebThemeEngine::PartRadio:
       return ui::NativeTheme::kRadio;
     case WebThemeEngine::PartButton:
       return ui::NativeTheme::kPushButton;
     case WebThemeEngine::PartTextField:
       return ui::NativeTheme::kTextField;
     case WebThemeEngine::PartMenuList:
       return ui::NativeTheme::kMenuList;
@@ skipping 101 matching lines @@
           extra_params->progressBar.valueRectWidth;
       native_theme_extra_params->progress_bar.value_rect_height =
           extra_params->progressBar.valueRectHeight;
       break;
     default:
       break;  // Parts that have no extra params get here.
   }
 }
 
 blink::WebSize WebThemeEngineImpl::getSize(WebThemeEngine::Part part) {
-  ui::NativeTheme::ExtraParams extra;
-  return ui::NativeTheme::GetInstanceForWeb()->GetPartSize(
-      NativeThemePart(part), ui::NativeTheme::kNormal, extra);
+  switch (part) {
+    case ui::NativeTheme::kScrollbarHorizontalThumb:
+    case ui::NativeTheme::kScrollbarVerticalThumb: {
+      // Minimum length for scrollbar thumb is the scrollbar thickness.
+      ScrollbarStyle style;
+      getOverlayScrollbarStyle(&style);
+      int scrollbarThickness = style.thumbThickness + style.scrollbarMargin;
+      return gfx::Size(scrollbarThickness, scrollbarThickness);
+    }
+    default: {
+      ui::NativeTheme::ExtraParams extra;
+      return ui::NativeTheme::GetInstanceForWeb()->GetPartSize(
+          NativeThemePart(part), ui::NativeTheme::kNormal, extra);
+    }
+  }
 }
 
 void WebThemeEngineImpl::getOverlayScrollbarStyle(ScrollbarStyle* style) {
   // TODO(bokan): Android scrollbars on non-composited scrollers don't
   // currently fade out so the fadeOutDuration and Delay  Now that this has
   // been added into Blink for other platforms we should plumb that through for
   // Android as well.
   style->fadeOutDelaySeconds = 0;
   style->fadeOutDurationSeconds = 0;
   if (getMajorVersion() >= kVersionLollipop) {
@@ skipping 14 matching lines @@
     const blink::WebRect& rect,
     const WebThemeEngine::ExtraParams* extra_params) {
   ui::NativeTheme::ExtraParams native_theme_extra_params;
   GetNativeThemeExtraParams(
       part, state, extra_params, &native_theme_extra_params);
   ui::NativeTheme::GetInstanceForWeb()->Paint(
       canvas, NativeThemePart(part), NativeThemeState(state), gfx::Rect(rect),
       native_theme_extra_params);
 }
 }  // namespace content