widget/nsNativeTheme.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "nsNativeTheme.h"
   7 #include "nsIWidget.h"
   8 #include "mozilla/dom/Document.h"
   9 #include "nsIContent.h"
  10 #include "nsIFrame.h"
  11 #include "nsIScrollableFrame.h"
  12 #include "nsLayoutUtils.h"
  13 #include "nsNumberControlFrame.h"
  14 #include "nsPresContext.h"
  15 #include "nsString.h"
  16 #include "nsNameSpaceManager.h"
  17 #include "nsStyleConsts.h"
  18 #include "nsPIDOMWindow.h"
  19 #include "nsProgressFrame.h"
  20 #include "nsMeterFrame.h"
  21 #include "nsMenuFrame.h"
  22 #include "nsRangeFrame.h"
  23 #include "nsCSSRendering.h"
  24 #include "ImageContainer.h"
  25 #include "mozilla/ComputedStyle.h"
  26 #include "mozilla/dom/Element.h"
  27 #include "mozilla/dom/HTMLBodyElement.h"
  28 #include "mozilla/dom/HTMLInputElement.h"
  29 #include "mozilla/dom/HTMLProgressElement.h"
  30 #include "mozilla/PresShell.h"
  31 #include "mozilla/StaticPrefs_layout.h"
  32 #include "mozilla/dom/DocumentInlines.h"
  33 #include <algorithm>
  34
  35 using namespace mozilla;
  36 using namespace mozilla::dom;
  37
  38 nsNativeTheme::nsNativeTheme() : mAnimatedContentTimeout(UINT32_MAX) {}
  39
  40 NS_IMPL_ISUPPORTS(nsNativeTheme, nsITimerCallback, nsINamed)
  41
  42 /* static */ ElementState nsNativeTheme::GetContentState(
  43     nsIFrame* aFrame, StyleAppearance aAppearance) {
  44   if (!aFrame) {
  45     return ElementState();
  46   }
  47
  48   nsIContent* frameContent = aFrame->GetContent();
  49   if (!frameContent || !frameContent->IsElement()) {
  50     return ElementState();
  51   }
  52
  53   const bool isXULElement = frameContent->IsXULElement();
  54   if (isXULElement) {
  55     if (aAppearance == StyleAppearance::CheckboxLabel ||
  56         aAppearance == StyleAppearance::RadioLabel) {
  57       aFrame = aFrame->GetParent()->GetParent();
  58       frameContent = aFrame->GetContent();
  59     } else if (aAppearance == StyleAppearance::Checkbox ||
  60                aAppearance == StyleAppearance::Radio ||
  61                aAppearance == StyleAppearance::ToolbarbuttonDropdown ||
  62                aAppearance == StyleAppearance::Treeheadersortarrow ||
  63                aAppearance == StyleAppearance::ButtonArrowPrevious ||
  64                aAppearance == StyleAppearance::ButtonArrowNext ||
  65                aAppearance == StyleAppearance::ButtonArrowUp ||
  66                aAppearance == StyleAppearance::ButtonArrowDown) {
  67       aFrame = aFrame->GetParent();
  68       frameContent = aFrame->GetContent();
  69     }
  70     MOZ_ASSERT(frameContent && frameContent->IsElement());
  71   }
  72
  73   ElementState flags = frameContent->AsElement()->StyleState();
  74   nsNumberControlFrame* numberControlFrame =
  75       nsNumberControlFrame::GetNumberControlFrameForSpinButton(aFrame);
  76   if (numberControlFrame &&
  77       numberControlFrame->GetContent()->AsElement()->StyleState().HasState(
  78           ElementState::DISABLED)) {
  79     flags |= ElementState::DISABLED;
  80   }
  81
  82   if (!isXULElement) {
  83     return flags;
  84   }
  85
  86   if (CheckBooleanAttr(aFrame, nsGkAtoms::disabled)) {
  87     flags |= ElementState::DISABLED;
  88   }
  89
  90   switch (aAppearance) {
  91     case StyleAppearance::RadioLabel:
  92     case StyleAppearance::Radio: {
  93       if (CheckBooleanAttr(aFrame, nsGkAtoms::focused)) {
  94         flags |= ElementState::FOCUS;
  95         nsPIDOMWindowOuter* window =
  96             aFrame->GetContent()->OwnerDoc()->GetWindow();
  97         if (window && window->ShouldShowFocusRing()) {
  98           flags |= ElementState::FOCUSRING;
  99         }
 100       }
 101       if (CheckBooleanAttr(aFrame, nsGkAtoms::selected)) {
 102         flags |= ElementState::CHECKED;
 103       }
 104       break;
 105     }
 106     case StyleAppearance::CheckboxLabel:
 107     case StyleAppearance::Checkbox: {
 108       if (CheckBooleanAttr(aFrame, nsGkAtoms::checked)) {
 109         flags |= ElementState::CHECKED;
 110       } else if (CheckBooleanAttr(aFrame, nsGkAtoms::indeterminate)) {
 111         flags |= ElementState::INDETERMINATE;
 112       }
 113       break;
 114     }
 115     case StyleAppearance::MenulistButton:
 116     case StyleAppearance::Menulist:
 117     case StyleAppearance::NumberInput:
 118     case StyleAppearance::Textfield:
 119     case StyleAppearance::Searchfield:
 120     case StyleAppearance::Textarea: {
 121       if (CheckBooleanAttr(aFrame, nsGkAtoms::focused)) {
 122         flags |= ElementState::FOCUS | ElementState::FOCUSRING;
 123       }
 124       break;
 125     }
 126     default:
 127       break;
 128   }
 129
 130   return flags;
 131 }
 132
 133 /* static */
 134 bool nsNativeTheme::CheckBooleanAttr(nsIFrame* aFrame, nsAtom* aAtom) {
 135   if (!aFrame) return false;
 136
 137   nsIContent* content = aFrame->GetContent();
 138   if (!content || !content->IsElement()) return false;
 139
 140   if (content->IsHTMLElement())
 141     return content->AsElement()->HasAttr(kNameSpaceID_None, aAtom);
 142
 143   // For XML/XUL elements, an attribute must be equal to the literal
 144   // string "true" to be counted as true.  An empty string should _not_
 145   // be counted as true.
 146   return content->AsElement()->AttrValueIs(kNameSpaceID_None, aAtom, u"true"_ns,
 147                                            eCaseMatters);
 148 }
 149
 150 /* static */
 151 int32_t nsNativeTheme::CheckIntAttr(nsIFrame* aFrame, nsAtom* aAtom,
 152                                     int32_t defaultValue) {
 153   if (!aFrame) return defaultValue;
 154
 155   nsIContent* content = aFrame->GetContent();
 156   if (!content || !content->IsElement()) return defaultValue;
 157
 158   nsAutoString attr;
 159   content->AsElement()->GetAttr(kNameSpaceID_None, aAtom, attr);
 160   nsresult err;
 161   int32_t value = attr.ToInteger(&err);
 162   if (attr.IsEmpty() || NS_FAILED(err)) return defaultValue;
 163
 164   return value;
 165 }
 166
 167 /* static */
 168 double nsNativeTheme::GetProgressValue(nsIFrame* aFrame) {
 169   if (!aFrame || !aFrame->GetContent()->IsHTMLElement(nsGkAtoms::progress)) {
 170     return 0;
 171   }
 172
 173   return static_cast<HTMLProgressElement*>(aFrame->GetContent())->Value();
 174 }
 175
 176 /* static */
 177 double nsNativeTheme::GetProgressMaxValue(nsIFrame* aFrame) {
 178   if (!aFrame || !aFrame->GetContent()->IsHTMLElement(nsGkAtoms::progress)) {
 179     return 100;
 180   }
 181
 182   return static_cast<HTMLProgressElement*>(aFrame->GetContent())->Max();
 183 }
 184
 185 bool nsNativeTheme::IsButtonTypeMenu(nsIFrame* aFrame) {
 186   if (!aFrame) return false;
 187
 188   nsIContent* content = aFrame->GetContent();
 189   return content->IsXULElement(nsGkAtoms::button) &&
 190          content->AsElement()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::type,
 191                                            u"menu"_ns, eCaseMatters);
 192 }
 193
 194 bool nsNativeTheme::IsPressedButton(nsIFrame* aFrame) {
 195   ElementState state = GetContentState(aFrame, StyleAppearance::Toolbarbutton);
 196   if (state.HasState(ElementState::DISABLED)) {
 197     return false;
 198   }
 199
 200   return IsOpenButton(aFrame) ||
 201          state.HasAllStates(ElementState::ACTIVE | ElementState::HOVER);
 202 }
 203
 204 bool nsNativeTheme::IsWidgetStyled(nsPresContext* aPresContext,
 205                                    nsIFrame* aFrame,
 206                                    StyleAppearance aAppearance) {
 207   // Check for specific widgets to see if HTML has overridden the style.
 208   if (!aFrame) {
 209     return false;
 210   }
 211
 212   // Resizers have some special handling, dependent on whether in a scrollable
 213   // container or not. If so, use the scrollable container's to determine
 214   // whether the style is overriden instead of the resizer. This allows a
 215   // non-native transparent resizer to be used instead. Otherwise, we just
 216   // fall through and return false.
 217   if (aAppearance == StyleAppearance::Resizer) {
 218     nsIFrame* parentFrame = aFrame->GetParent();
 219     if (parentFrame && parentFrame->IsScrollFrame()) {
 220       // if the parent is a scrollframe, the resizer should be native themed
 221       // only if the scrollable area doesn't override the widget style.
 222       //
 223       // note that the condition below looks a bit suspect but it's the right
 224       // one. If there's no valid appearance, then we should return true, it's
 225       // effectively the same as if it had overridden the appearance.
 226       parentFrame = parentFrame->GetParent();
 227       if (!parentFrame) {
 228         return false;
 229       }
 230       auto parentAppearance =
 231           parentFrame->StyleDisplay()->EffectiveAppearance();
 232       return parentAppearance == StyleAppearance::None ||
 233              IsWidgetStyled(aPresContext, parentFrame, parentAppearance);
 234     }
 235   }
 236
 237   /**
 238    * Progress bar appearance should be the same for the bar and the container
 239    * frame. nsProgressFrame owns the logic and will tell us what we should do.
 240    */
 241   if (aAppearance == StyleAppearance::Progresschunk ||
 242       aAppearance == StyleAppearance::ProgressBar) {
 243     nsProgressFrame* progressFrame = do_QueryFrame(
 244         aAppearance == StyleAppearance::Progresschunk ? aFrame->GetParent()
 245                                                       : aFrame);
 246     if (progressFrame) {
 247       return !progressFrame->ShouldUseNativeStyle();
 248     }
 249   }
 250
 251   /**
 252    * Meter bar appearance should be the same for the bar and the container
 253    * frame. nsMeterFrame owns the logic and will tell us what we should do.
 254    */
 255   if (aAppearance == StyleAppearance::Meterchunk ||
 256       aAppearance == StyleAppearance::Meter) {
 257     nsMeterFrame* meterFrame = do_QueryFrame(
 258         aAppearance == StyleAppearance::Meterchunk ? aFrame->GetParent()
 259                                                    : aFrame);
 260     if (meterFrame) {
 261       return !meterFrame->ShouldUseNativeStyle();
 262     }
 263   }
 264
 265   /**
 266    * An nsRangeFrame and its children are treated atomically when it
 267    * comes to native theming (either all parts, or no parts, are themed).
 268    * nsRangeFrame owns the logic and will tell us what we should do.
 269    */
 270   if (aAppearance == StyleAppearance::Range ||
 271       aAppearance == StyleAppearance::RangeThumb) {
 272     nsRangeFrame* rangeFrame = do_QueryFrame(
 273         aAppearance == StyleAppearance::RangeThumb ? aFrame->GetParent()
 274                                                    : aFrame);
 275     if (rangeFrame) {
 276       return !rangeFrame->ShouldUseNativeStyle();
 277     }
 278   }
 279
 280   return nsLayoutUtils::AuthorSpecifiedBorderBackgroundDisablesTheming(
 281              aAppearance) &&
 282          aFrame->GetContent()->IsHTMLElement() &&
 283          aFrame->Style()->HasAuthorSpecifiedBorderOrBackground();
 284 }
 285
 286 /* static */
 287 bool nsNativeTheme::IsFrameRTL(nsIFrame* aFrame) {
 288   if (!aFrame) {
 289     return false;
 290   }
 291   return aFrame->GetWritingMode().IsPhysicalRTL();
 292 }
 293
 294 /* static */
 295 bool nsNativeTheme::IsHTMLContent(nsIFrame* aFrame) {
 296   if (!aFrame) {
 297     return false;
 298   }
 299   nsIContent* content = aFrame->GetContent();
 300   return content && content->IsHTMLElement();
 301 }
 302
 303 // treeheadercell:
 304 nsNativeTheme::TreeSortDirection nsNativeTheme::GetTreeSortDirection(
 305     nsIFrame* aFrame) {
 306   if (!aFrame || !aFrame->GetContent()) return eTreeSortDirection_Natural;
 307
 308   static Element::AttrValuesArray strings[] = {nsGkAtoms::descending,
 309                                                nsGkAtoms::ascending, nullptr};
 310
 311   nsIContent* content = aFrame->GetContent();
 312   if (content->IsElement()) {
 313     switch (content->AsElement()->FindAttrValueIn(
 314         kNameSpaceID_None, nsGkAtoms::sortDirection, strings, eCaseMatters)) {
 315       case 0:
 316         return eTreeSortDirection_Descending;
 317       case 1:
 318         return eTreeSortDirection_Ascending;
 319     }
 320   }
 321
 322   return eTreeSortDirection_Natural;
 323 }
 324
 325 bool nsNativeTheme::IsLastTreeHeaderCell(nsIFrame* aFrame) {
 326   if (!aFrame) return false;
 327
 328   // A tree column picker is always the last header cell.
 329   if (aFrame->GetContent()->IsXULElement(nsGkAtoms::treecolpicker)) return true;
 330
 331   // Find the parent tree.
 332   nsIContent* parent = aFrame->GetContent()->GetParent();
 333   while (parent && !parent->IsXULElement(nsGkAtoms::tree)) {
 334     parent = parent->GetParent();
 335   }
 336
 337   // If the column picker is visible, this can't be the last column.
 338   if (parent && !parent->AsElement()->AttrValueIs(kNameSpaceID_None,
 339                                                   nsGkAtoms::hidecolumnpicker,
 340                                                   u"true"_ns, eCaseMatters))
 341     return false;
 342
 343   while ((aFrame = aFrame->GetNextSibling())) {
 344     if (aFrame->GetRect().Width() > 0) return false;
 345   }
 346   return true;
 347 }
 348
 349 // tab:
 350 bool nsNativeTheme::IsBottomTab(nsIFrame* aFrame) {
 351   if (!aFrame) return false;
 352
 353   nsAutoString classStr;
 354   if (aFrame->GetContent()->IsElement()) {
 355     aFrame->GetContent()->AsElement()->GetAttr(kNameSpaceID_None,
 356                                                nsGkAtoms::_class, classStr);
 357   }
 358   // FIXME: This looks bogus, shouldn't this be looking at GetClasses()?
 359   return !classStr.IsEmpty() && classStr.Find(u"tab-bottom") != kNotFound;
 360 }
 361
 362 bool nsNativeTheme::IsFirstTab(nsIFrame* aFrame) {
 363   if (!aFrame) return false;
 364
 365   for (nsIFrame* first : aFrame->GetParent()->PrincipalChildList()) {
 366     if (first->GetRect().Width() > 0 &&
 367         first->GetContent()->IsXULElement(nsGkAtoms::tab))
 368       return (first == aFrame);
 369   }
 370   return false;
 371 }
 372
 373 bool nsNativeTheme::IsHorizontal(nsIFrame* aFrame) {
 374   if (!aFrame) return false;
 375
 376   if (!aFrame->GetContent()->IsElement()) return true;
 377
 378   return !aFrame->GetContent()->AsElement()->AttrValueIs(
 379       kNameSpaceID_None, nsGkAtoms::orient, nsGkAtoms::vertical, eCaseMatters);
 380 }
 381
 382 bool nsNativeTheme::IsNextToSelectedTab(nsIFrame* aFrame, int32_t aOffset) {
 383   if (!aFrame) return false;
 384
 385   if (aOffset == 0) return IsSelectedTab(aFrame);
 386
 387   int32_t thisTabIndex = -1, selectedTabIndex = -1;
 388
 389   nsIFrame* currentTab = aFrame->GetParent()->PrincipalChildList().FirstChild();
 390   for (int32_t i = 0; currentTab; currentTab = currentTab->GetNextSibling()) {
 391     if (currentTab->GetRect().Width() == 0) continue;
 392     if (aFrame == currentTab) thisTabIndex = i;
 393     if (IsSelectedTab(currentTab)) selectedTabIndex = i;
 394     ++i;
 395   }
 396
 397   if (thisTabIndex == -1 || selectedTabIndex == -1) return false;
 398
 399   return (thisTabIndex - selectedTabIndex == aOffset);
 400 }
 401
 402 bool nsNativeTheme::IsVerticalProgress(nsIFrame* aFrame) {
 403   if (!aFrame) {
 404     return false;
 405   }
 406   return IsVerticalMeter(aFrame);
 407 }
 408
 409 bool nsNativeTheme::IsVerticalMeter(nsIFrame* aFrame) {
 410   MOZ_ASSERT(aFrame, "You have to pass a non-null aFrame");
 411   switch (aFrame->StyleDisplay()->mOrient) {
 412     case StyleOrient::Horizontal:
 413       return false;
 414     case StyleOrient::Vertical:
 415       return true;
 416     case StyleOrient::Inline:
 417       return aFrame->GetWritingMode().IsVertical();
 418     case StyleOrient::Block:
 419       return !aFrame->GetWritingMode().IsVertical();
 420   }
 421   MOZ_ASSERT_UNREACHABLE("unexpected -moz-orient value");
 422   return false;
 423 }
 424
 425 // menupopup:
 426 bool nsNativeTheme::IsSubmenu(nsIFrame* aFrame, bool* aLeftOfParent) {
 427   if (!aFrame) return false;
 428
 429   nsIContent* parentContent = aFrame->GetContent()->GetParent();
 430   if (!parentContent || !parentContent->IsXULElement(nsGkAtoms::menu))
 431     return false;
 432
 433   nsIFrame* parent = aFrame;
 434   while ((parent = parent->GetParent())) {
 435     if (parent->GetContent() == parentContent) {
 436       if (aLeftOfParent) {
 437         LayoutDeviceIntRect selfBounds, parentBounds;
 438         selfBounds = aFrame->GetNearestWidget()->GetScreenBounds();
 439         parentBounds = parent->GetNearestWidget()->GetScreenBounds();
 440         *aLeftOfParent = selfBounds.X() < parentBounds.X();
 441       }
 442       return true;
 443     }
 444   }
 445
 446   return false;
 447 }
 448
 449 bool nsNativeTheme::QueueAnimatedContentForRefresh(nsIContent* aContent,
 450                                                    uint32_t aMinimumFrameRate) {
 451   NS_ASSERTION(aContent, "Null pointer!");
 452   NS_ASSERTION(aMinimumFrameRate, "aMinimumFrameRate must be non-zero!");
 453   NS_ASSERTION(aMinimumFrameRate <= 1000,
 454                "aMinimumFrameRate must be less than 1000!");
 455
 456   uint32_t timeout = 1000 / aMinimumFrameRate;
 457   timeout = std::min(mAnimatedContentTimeout, timeout);
 458
 459   if (!mAnimatedContentTimer) {
 460     mAnimatedContentTimer = NS_NewTimer();
 461     NS_ENSURE_TRUE(mAnimatedContentTimer, false);
 462   }
 463
 464   if (mAnimatedContentList.IsEmpty() || timeout != mAnimatedContentTimeout) {
 465     nsresult rv;
 466     if (!mAnimatedContentList.IsEmpty()) {
 467       rv = mAnimatedContentTimer->Cancel();
 468       NS_ENSURE_SUCCESS(rv, false);
 469     }
 470
 471     if (XRE_IsContentProcess() && NS_IsMainThread()) {
 472       mAnimatedContentTimer->SetTarget(
 473           aContent->OwnerDoc()->EventTargetFor(TaskCategory::Other));
 474     }
 475     rv = mAnimatedContentTimer->InitWithCallback(this, timeout,
 476                                                  nsITimer::TYPE_ONE_SHOT);
 477     NS_ENSURE_SUCCESS(rv, false);
 478
 479     mAnimatedContentTimeout = timeout;
 480   }
 481
 482   // XXX(Bug 1631371) Check if this should use a fallible operation as it
 483   // pretended earlier.
 484   mAnimatedContentList.AppendElement(aContent);
 485
 486   return true;
 487 }
 488
 489 NS_IMETHODIMP
 490 nsNativeTheme::Notify(nsITimer* aTimer) {
 491   NS_ASSERTION(aTimer == mAnimatedContentTimer, "Wrong timer!");
 492
 493   // XXX Assumes that calling nsIFrame::Invalidate won't reenter
 494   //     QueueAnimatedContentForRefresh.
 495
 496   uint32_t count = mAnimatedContentList.Length();
 497   for (uint32_t index = 0; index < count; index++) {
 498     nsIFrame* frame = mAnimatedContentList[index]->GetPrimaryFrame();
 499     if (frame) {
 500       frame->InvalidateFrame();
 501     }
 502   }
 503
 504   mAnimatedContentList.Clear();
 505   mAnimatedContentTimeout = UINT32_MAX;
 506   return NS_OK;
 507 }
 508
 509 NS_IMETHODIMP
 510 nsNativeTheme::GetName(nsACString& aName) {
 511   aName.AssignLiteral("nsNativeTheme");
 512   return NS_OK;
 513 }
 514
 515 nsIFrame* nsNativeTheme::GetAdjacentSiblingFrameWithSameAppearance(
 516     nsIFrame* aFrame, bool aNextSibling) {
 517   if (!aFrame) return nullptr;
 518
 519   // Find the next visible sibling.
 520   nsIFrame* sibling = aFrame;
 521   do {
 522     sibling =
 523         aNextSibling ? sibling->GetNextSibling() : sibling->GetPrevSibling();
 524   } while (sibling && sibling->GetRect().Width() == 0);
 525
 526   // Check same appearance and adjacency.
 527   if (!sibling ||
 528       sibling->StyleDisplay()->EffectiveAppearance() !=
 529           aFrame->StyleDisplay()->EffectiveAppearance() ||
 530       (sibling->GetRect().XMost() != aFrame->GetRect().X() &&
 531        aFrame->GetRect().XMost() != sibling->GetRect().X()))
 532     return nullptr;
 533   return sibling;
 534 }
 535
 536 bool nsNativeTheme::IsRangeHorizontal(nsIFrame* aFrame) {
 537   nsIFrame* rangeFrame = aFrame;
 538   if (!rangeFrame->IsRangeFrame()) {
 539     // If the thumb's frame is passed in, get its range parent:
 540     rangeFrame = aFrame->GetParent();
 541   }
 542   if (rangeFrame->IsRangeFrame()) {
 543     return static_cast<nsRangeFrame*>(rangeFrame)->IsHorizontal();
 544   }
 545   // Not actually a range frame - just use the ratio of the frame's size to
 546   // decide:
 547   return aFrame->GetSize().width >= aFrame->GetSize().height;
 548 }
 549
 550 /* static */
 551 bool nsNativeTheme::IsDarkBackgroundForScrollbar(nsIFrame* aFrame) {
 552   // Try to find the scrolled frame. Note that for stuff like xul <tree> there
 553   // might be none.
 554   {
 555     nsIFrame* frame = aFrame;
 556     nsIScrollableFrame* scrollFrame = nullptr;
 557     while (!scrollFrame && frame) {
 558       scrollFrame = frame->GetScrollTargetFrame();
 559       frame = frame->GetParent();
 560     }
 561     if (scrollFrame) {
 562       aFrame = scrollFrame->GetScrolledFrame();
 563     } else {
 564       // Leave aFrame untouched.
 565     }
 566   }
 567
 568   return IsDarkBackground(aFrame);
 569 }
 570
 571 /* static */
 572 bool nsNativeTheme::IsDarkBackground(nsIFrame* aFrame) {
 573   auto color =
 574       nsCSSRendering::FindEffectiveBackgroundColor(
 575           aFrame, /* aStopAtThemed = */ false, /* aPreferBodyToCanvas = */ true)
 576           .mColor;
 577   return LookAndFeel::IsDarkColor(color);
 578 }
 579
 580 /*static*/
 581 bool nsNativeTheme::IsWidgetScrollbarPart(StyleAppearance aAppearance) {
 582   switch (aAppearance) {
 583     case StyleAppearance::ScrollbarVertical:
 584     case StyleAppearance::ScrollbarHorizontal:
 585     case StyleAppearance::ScrollbarbuttonUp:
 586     case StyleAppearance::ScrollbarbuttonDown:
 587     case StyleAppearance::ScrollbarbuttonLeft:
 588     case StyleAppearance::ScrollbarbuttonRight:
 589     case StyleAppearance::ScrollbarthumbVertical:
 590     case StyleAppearance::ScrollbarthumbHorizontal:
 591     case StyleAppearance::ScrollbartrackHorizontal:
 592     case StyleAppearance::ScrollbartrackVertical:
 593     case StyleAppearance::Scrollcorner:
 594       return true;
 595     default:
 596       return false;
 597   }
 598 }