Fix scrollbar buttons at hidpi when enable-use-zoom-for-dsf is on.

content/child/webthemeengine_impl_default.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_default.h"
 
 #include "build/build_config.h"
 #include "skia/ext/platform_canvas.h"
 #include "third_party/WebKit/public/platform/WebRect.h"
 #include "third_party/WebKit/public/platform/WebSize.h"
 #include "ui/native_theme/native_theme.h"
 
 using blink::WebCanvas;
 using blink::WebColor;
 using blink::WebRect;
 using blink::WebThemeEngine;
 
 namespace content {
-namespace {
-
-#if defined(OS_WIN)
-// The scrollbar metrics default to 17 dips which is the default value on
-// Windows in most cases.
-int32_t g_vertical_scroll_bar_width = 17;

[esprehn, 2016/04/25 23:12:11]

what sets these values now?

[Bret, 2016/04/25 23:24:32]

Nothing, they were only used in the vestigial pre-hidpi case that I fixed in
ScrollbarThemeAura.

-
-// The height of a horizontal scroll bar in dips.
-int32_t g_horizontal_scroll_bar_height = 17;
-
-// The height of the arrow bitmap on a vertical scroll bar in dips.
-int32_t g_vertical_arrow_bitmap_height = 17;
-
-// The width of the arrow bitmap on a horizontal scroll bar in dips.
-int32_t g_horizontal_arrow_bitmap_width = 17;
-#endif
-
-}  // namespace
 
 static ui::NativeTheme::Part NativeThemePart(
     WebThemeEngine::Part part) {
   switch (part) {
     case WebThemeEngine::PartScrollbarDownArrow:
       return ui::NativeTheme::kScrollbarDownArrow;
     case WebThemeEngine::PartScrollbarLeftArrow:
       return ui::NativeTheme::kScrollbarLeftArrow;
     case WebThemeEngine::PartScrollbarRightArrow:
       return ui::NativeTheme::kScrollbarRightArrow;
@@ skipping 131 matching lines @@
       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;
-  ui::NativeTheme::Part native_theme_part = NativeThemePart(part);
-#if defined(OS_WIN)
-  switch (native_theme_part) {
-    case ui::NativeTheme::kScrollbarDownArrow:
-    case ui::NativeTheme::kScrollbarLeftArrow:
-    case ui::NativeTheme::kScrollbarRightArrow:
-    case ui::NativeTheme::kScrollbarUpArrow:
-    case ui::NativeTheme::kScrollbarHorizontalThumb:
-    case ui::NativeTheme::kScrollbarVerticalThumb:
-    case ui::NativeTheme::kScrollbarHorizontalTrack:
-    case ui::NativeTheme::kScrollbarVerticalTrack: {
-      return gfx::Size(g_vertical_scroll_bar_width,
-                       g_vertical_scroll_bar_width);
-    }
-
-    default:
-      break;
-  }
-#endif
   return ui::NativeTheme::GetInstanceForWeb()->GetPartSize(
-      native_theme_part, ui::NativeTheme::kNormal, extra);
+      NativeThemePart(part), ui::NativeTheme::kNormal, extra);
 }
 
 void WebThemeEngineImpl::paint(
     blink::WebCanvas* canvas,
     WebThemeEngine::Part part,
     WebThemeEngine::State state,
     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);
 }
 
 void WebThemeEngineImpl::paintStateTransition(blink::WebCanvas* canvas,
                                               WebThemeEngine::Part part,
                                               WebThemeEngine::State startState,
                                               WebThemeEngine::State endState,
                                               double progress,
                                               const blink::WebRect& rect) {
   ui::NativeTheme::GetInstanceForWeb()->PaintStateTransition(
       canvas, NativeThemePart(part), NativeThemeState(startState),
       NativeThemeState(endState), progress, gfx::Rect(rect));
 }
 
-#if defined(OS_WIN)
-// static
-void WebThemeEngineImpl::cacheScrollBarMetrics(
-    int32_t vertical_scroll_bar_width,
-    int32_t horizontal_scroll_bar_height,
-    int32_t vertical_arrow_bitmap_height,
-    int32_t horizontal_arrow_bitmap_width) {
-  g_vertical_scroll_bar_width = vertical_scroll_bar_width;
-  g_horizontal_scroll_bar_height = horizontal_scroll_bar_height;
-  g_vertical_arrow_bitmap_height = vertical_arrow_bitmap_height;
-  g_horizontal_arrow_bitmap_width = horizontal_arrow_bitmap_width;
-}
-#endif
-
 }  // namespace content