Revert 98434 - Adding a Views scrollbar implementation.

views/controls/scrollbar/bitmap_scroll_bar.cc

Index: views/controls/scrollbar/bitmap_scroll_bar.cc
===================================================================
--- views/controls/scrollbar/bitmap_scroll_bar.cc	(revision 98466)
+++ views/controls/scrollbar/bitmap_scroll_bar.cc	(working copy)
@@ -19,7 +19,6 @@
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/gfx/canvas.h"
 #include "views/controls/menu/menu.h"
-#include "views/controls/scrollbar/base_scroll_bar_thumb.h"
 #include "views/controls/scroll_view.h"
 #include "views/widget/widget.h"
 
@@ -45,7 +44,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 class AutorepeatButton : public ImageButton {
  public:
-  explicit AutorepeatButton(ButtonListener* listener)
+  AutorepeatButton(ButtonListener* listener)
       : ImageButton(listener),
         ALLOW_THIS_IN_INITIALIZER_LIST(repeater_(
             NewCallback<AutorepeatButton>(this,
@@ -98,14 +97,59 @@
 //  drag to scroll the associated contents view within the viewport.
 //
 ///////////////////////////////////////////////////////////////////////////////
-class BitmapScrollBarThumb : public BaseScrollBarThumb {
+class BitmapScrollBarThumb : public View {
  public:
   explicit BitmapScrollBarThumb(BitmapScrollBar* scroll_bar)
-      : BaseScrollBarThumb(scroll_bar),
-        scroll_bar_(scroll_bar) {
+      : scroll_bar_(scroll_bar),
+        drag_start_position_(-1),
+        mouse_offset_(-1),
+        state_(CustomButton::BS_NORMAL) {
   }
   virtual ~BitmapScrollBarThumb() { }
 
+  // Sets the size (width or height) of the thumb to the specified value.
+  void SetSize(int size) {
+    // Make sure the thumb is never sized smaller than its minimum possible
+    // display size.
+    gfx::Size prefsize = GetPreferredSize();
+    size = std::max(size, scroll_bar_->IsHorizontal() ? prefsize.width() :
+                                                        prefsize.height());
+    gfx::Rect thumb_bounds = bounds();
+    if (scroll_bar_->IsHorizontal()) {
+      thumb_bounds.set_width(size);
+    } else {
+      thumb_bounds.set_height(size);
+    }
+    SetBoundsRect(thumb_bounds);
+  }
+
+  // Retrieves the size (width or height) of the thumb.
+  int GetSize() const {
+    if (scroll_bar_->IsHorizontal())
+      return width();
+    return height();
+  }
+
+  // Sets the position of the thumb on the x or y axis.
+  void SetPosition(int position) {
+    gfx::Rect thumb_bounds = bounds();
+    gfx::Rect track_bounds = scroll_bar_->GetTrackBounds();
+    if (scroll_bar_->IsHorizontal()) {
+      thumb_bounds.set_x(track_bounds.x() + position);
+    } else {
+      thumb_bounds.set_y(track_bounds.y() + position);
+    }
+    SetBoundsRect(thumb_bounds);
+  }
+
+  // Gets the position of the thumb on the x or y axis.
+  int GetPosition() const {
+    gfx::Rect track_bounds = scroll_bar_->GetTrackBounds();
+    if (scroll_bar_->IsHorizontal())
+      return x() - track_bounds.x();
+    return y() - track_bounds.y();
+  }
+
   // View overrides:
   virtual gfx::Size GetPreferredSize() OVERRIDE {
     return gfx::Size(background_bitmap()->width(),
@@ -116,7 +160,7 @@
 
  protected:
   // View overrides:
-  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE {
+  virtual void Paint(gfx::Canvas* canvas) OVERRIDE {
     canvas->DrawBitmapInt(*start_cap_bitmap(), 0, 0);
     int top_cap_height = start_cap_bitmap()->height();
     int bottom_cap_height = end_cap_bitmap()->height();
@@ -132,21 +176,71 @@
     canvas->DrawBitmapInt(*grippy_bitmap(), grippy_x, grippy_y);
   }
 
+  virtual void OnMouseEntered(const MouseEvent& event) OVERRIDE {
+    SetState(CustomButton::BS_HOT);
+  }
+
+  virtual void OnMouseExited(const MouseEvent& event) OVERRIDE {
+    SetState(CustomButton::BS_NORMAL);
+  }
+
+  virtual bool OnMousePressed(const MouseEvent& event) OVERRIDE {
+    mouse_offset_ = scroll_bar_->IsHorizontal() ? event.x() : event.y();
+    drag_start_position_ = GetPosition();
+    SetState(CustomButton::BS_PUSHED);
+    return true;
+  }
+
+  virtual bool OnMouseDragged(const MouseEvent& event) OVERRIDE {
+    // If the user moves the mouse more than |kScrollThumbDragOutSnap| outside
+    // the bounds of the thumb, the scrollbar will snap the scroll back to the
+    // point it was at before the drag began.
+    if (scroll_bar_->IsHorizontal()) {
+      if ((event.y() < y() - kScrollThumbDragOutSnap) ||
+          (event.y() > (y() + height() + kScrollThumbDragOutSnap))) {
+        scroll_bar_->ScrollToThumbPosition(drag_start_position_, false);
+        return true;
+      }
+    } else {
+      if ((event.x() < x() - kScrollThumbDragOutSnap) ||
+          (event.x() > (x() + width() + kScrollThumbDragOutSnap))) {
+        scroll_bar_->ScrollToThumbPosition(drag_start_position_, false);
+        return true;
+      }
+    }
+    if (scroll_bar_->IsHorizontal()) {
+      int thumb_x = event.x() - mouse_offset_;
+      scroll_bar_->ScrollToThumbPosition(x() + thumb_x, false);
+    } else {
+      int thumb_y = event.y() - mouse_offset_;
+      scroll_bar_->ScrollToThumbPosition(y() + thumb_y, false);
+    }
+    return true;
+  }
+
+  virtual void OnMouseReleased(const MouseEvent& event) OVERRIDE {
+    OnMouseCaptureLost();
+  }
+
+  virtual void OnMouseCaptureLost() OVERRIDE {
+    SetState(CustomButton::BS_HOT);
+  }
+
  private:
   // Returns the bitmap rendered at the start of the thumb.
   SkBitmap* start_cap_bitmap() const {
-    return scroll_bar_->images_[BitmapScrollBar::THUMB_START_CAP][GetState()];
+    return scroll_bar_->images_[BitmapScrollBar::THUMB_START_CAP][state_];
   }
 
   // Returns the bitmap rendered at the end of the thumb.
   SkBitmap* end_cap_bitmap() const {
-    return scroll_bar_->images_[BitmapScrollBar::THUMB_END_CAP][GetState()];
+    return scroll_bar_->images_[BitmapScrollBar::THUMB_END_CAP][state_];
   }
 
   // Returns the bitmap that is tiled in the background of the thumb between
   // the start and the end caps.
   SkBitmap* background_bitmap() const {
-    return scroll_bar_->images_[BitmapScrollBar::THUMB_MIDDLE][GetState()];
+    return scroll_bar_->images_[BitmapScrollBar::THUMB_MIDDLE][state_];
   }
 
   // Returns the bitmap that is rendered in the middle of the thumb
@@ -156,9 +250,24 @@
         [CustomButton::BS_NORMAL];
   }
 
+  // Update our state and schedule a repaint when the mouse moves over us.
+  void SetState(CustomButton::ButtonState state) {
+    state_ = state;
+    SchedulePaint();
+  }
+
   // The BitmapScrollBar that owns us.
   BitmapScrollBar* scroll_bar_;
 
+  int drag_start_position_;
+
+  // The position of the mouse on the scroll axis relative to the top of this
+  // View when the drag started.
+  int mouse_offset_;
+
+  // The current state of the thumb button.
+  CustomButton::ButtonState state_;
+
   DISALLOW_COPY_AND_ASSIGN(BitmapScrollBarThumb);
 };
 
@@ -168,10 +277,19 @@
 // BitmapScrollBar, public:
 
 BitmapScrollBar::BitmapScrollBar(bool horizontal, bool show_scroll_buttons)
-    : BaseScrollBar(horizontal, new BitmapScrollBarThumb(this)),
+    : contents_size_(0),
+      contents_scroll_offset_(0),
       ALLOW_THIS_IN_INITIALIZER_LIST(prev_button_(new AutorepeatButton(this))),
       ALLOW_THIS_IN_INITIALIZER_LIST(next_button_(new AutorepeatButton(this))),
-      show_scroll_buttons_(show_scroll_buttons) {
+      ALLOW_THIS_IN_INITIALIZER_LIST(thumb_(new BitmapScrollBarThumb(this))),
+      thumb_track_state_(CustomButton::BS_NORMAL),
+      last_scroll_amount_(SCROLL_NONE),
+      ALLOW_THIS_IN_INITIALIZER_LIST(repeater_(
+          NewCallback<BitmapScrollBar>(this,
+                                       &BitmapScrollBar::TrackClicked))),
+      context_menu_mouse_position_(0),
+      show_scroll_buttons_(show_scroll_buttons),
+      ScrollBar(horizontal) {
   if (!show_scroll_buttons_) {
     prev_button_->SetVisible(false);
     next_button_->SetVisible(false);
@@ -179,12 +297,31 @@
 
   AddChildView(prev_button_);
   AddChildView(next_button_);
+  AddChildView(thumb_);
 
   set_context_menu_controller(this);
   prev_button_->set_context_menu_controller(this);
   next_button_->set_context_menu_controller(this);
+  thumb_->set_context_menu_controller(this);
 }
 
+gfx::Rect BitmapScrollBar::GetTrackBounds() const {
+  gfx::Size prefsize = prev_button_->GetPreferredSize();
+  if (IsHorizontal()) {
+    if (!show_scroll_buttons_)
+      prefsize.set_width(0);
+    int new_width =
+        std::max(0, width() - (prefsize.width() * 2));
+    gfx::Rect track_bounds(prefsize.width(), 0, new_width, prefsize.height());
+    return track_bounds;
+  }
+  if (!show_scroll_buttons_)
+    prefsize.set_height(0);
+  gfx::Rect track_bounds(0, prefsize.height(), prefsize.width(),
+                         std::max(0, height() - (prefsize.height() * 2)));
+  return track_bounds;
+}
+
 void BitmapScrollBar::SetImage(ScrollBarPart part,
                                CustomButton::ButtonState state,
                                SkBitmap* bitmap) {
@@ -207,28 +344,60 @@
   }
 }
 
-int BitmapScrollBar::GetLayoutSize() const {
-  gfx::Size prefsize = prev_button_->GetPreferredSize();
-  return IsHorizontal() ? prefsize.height() : prefsize.width();
+void BitmapScrollBar::ScrollByAmount(ScrollAmount amount) {
+  ScrollBarController* controller = GetController();
+  int offset = contents_scroll_offset_;
+  switch (amount) {
+    case SCROLL_START:
+      offset = GetMinPosition();
+      break;
+    case SCROLL_END:
+      offset = GetMaxPosition();
+      break;
+    case SCROLL_PREV_LINE:
+      offset -= controller->GetScrollIncrement(this, false, false);
+      offset = std::max(GetMinPosition(), offset);
+      break;
+    case SCROLL_NEXT_LINE:
+      offset += controller->GetScrollIncrement(this, false, true);
+      offset = std::min(GetMaxPosition(), offset);
+      break;
+    case SCROLL_PREV_PAGE:
+      offset -= controller->GetScrollIncrement(this, true, false);
+      offset = std::max(GetMinPosition(), offset);
+      break;
+    case SCROLL_NEXT_PAGE:
+      offset += controller->GetScrollIncrement(this, true, true);
+      offset = std::min(GetMaxPosition(), offset);
+      break;
+  }
+  contents_scroll_offset_ = offset;
+  ScrollContentsToOffset();
 }
 
-gfx::Rect BitmapScrollBar::GetTrackBounds() const {
-  gfx::Size prefsize = prev_button_->GetPreferredSize();
-  if (IsHorizontal()) {
-    if (!show_scroll_buttons_)
-      prefsize.set_width(0);
-    int new_width =
-        std::max(0, width() - (prefsize.width() * 2));
-    gfx::Rect track_bounds(prefsize.width(), 0, new_width, prefsize.height());
-    return track_bounds;
+void BitmapScrollBar::ScrollToThumbPosition(int thumb_position,
+                                            bool scroll_to_middle) {
+  contents_scroll_offset_ =
+      CalculateContentsOffset(thumb_position, scroll_to_middle);
+  if (contents_scroll_offset_ < GetMinPosition()) {
+    contents_scroll_offset_ = GetMinPosition();
+  } else if (contents_scroll_offset_ > GetMaxPosition()) {
+    contents_scroll_offset_ = GetMaxPosition();
   }
-  if (!show_scroll_buttons_)
-    prefsize.set_height(0);
-  gfx::Rect track_bounds(0, prefsize.height(), prefsize.width(),
-                         std::max(0, height() - (prefsize.height() * 2)));
-  return track_bounds;
+  ScrollContentsToOffset();
+  SchedulePaint();
 }
 
+void BitmapScrollBar::ScrollByContentsOffset(int contents_offset) {
+  contents_scroll_offset_ -= contents_offset;
+  if (contents_scroll_offset_ < GetMinPosition()) {
+    contents_scroll_offset_ = GetMinPosition();
+  } else if (contents_scroll_offset_ > GetMaxPosition()) {
+    contents_scroll_offset_ = GetMaxPosition();
+  }
+  ScrollContentsToOffset();
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 // BitmapScrollBar, View implementation:
 
@@ -257,20 +426,19 @@
     next_button_->SetBounds(0, 0, 0, 0);
   }
 
-  BaseScrollBarThumb* thumb = GetThumb();
   // Size and place the thumb
-  gfx::Size thumb_prefsize = thumb->GetPreferredSize();
+  gfx::Size thumb_prefsize = thumb_->GetPreferredSize();
   gfx::Rect track_bounds = GetTrackBounds();
 
   // Preserve the height/width of the thumb (depending on orientation) as set
   // by the last call to |Update|, but coerce the width/height to be the
   // appropriate value for the bitmaps provided.
   if (IsHorizontal()) {
-    thumb->SetBounds(thumb->x(), thumb->y(), thumb->width(),
+    thumb_->SetBounds(thumb_->x(), thumb_->y(), thumb_->width(),
                       thumb_prefsize.height());
   } else {
-    thumb->SetBounds(thumb->x(), thumb->y(), thumb_prefsize.width(),
-                     thumb->height());
+    thumb_->SetBounds(thumb_->x(), thumb_->y(), thumb_prefsize.width(),
+                      thumb_->height());
   }
 
   // Hide the thumb if the track isn't tall enough to display even a tiny
@@ -278,24 +446,199 @@
   // in this scenario.
   if ((IsHorizontal() && (track_bounds.width() < thumb_prefsize.width()) ||
       (!IsHorizontal() && (track_bounds.height() < thumb_prefsize.height())))) {
-    thumb->SetVisible(false);
-  } else if (!thumb->IsVisible()) {
-    thumb->SetVisible(true);
+    thumb_->SetVisible(false);
+  } else if (!thumb_->IsVisible()) {
+    thumb_->SetVisible(true);
   }
 }
 
+bool BitmapScrollBar::OnMousePressed(const MouseEvent& event) {
+  if (event.IsOnlyLeftMouseButton()) {
+    SetThumbTrackState(CustomButton::BS_PUSHED);
+    gfx::Rect thumb_bounds = thumb_->bounds();
+    if (IsHorizontal()) {
+      if (event.x() < thumb_bounds.x()) {
+        last_scroll_amount_ = SCROLL_PREV_PAGE;
+      } else if (event.x() > thumb_bounds.right()) {
+        last_scroll_amount_ = SCROLL_NEXT_PAGE;
+      }
+    } else {
+      if (event.y() < thumb_bounds.y()) {
+        last_scroll_amount_ = SCROLL_PREV_PAGE;
+      } else if (event.y() > thumb_bounds.bottom()) {
+        last_scroll_amount_ = SCROLL_NEXT_PAGE;
+      }
+    }
+    TrackClicked();
+    repeater_.Start();
+  }
+  return true;
+}
+
+void BitmapScrollBar::OnMouseReleased(const MouseEvent& event) {
+  OnMouseCaptureLost();
+}
+
+void BitmapScrollBar::OnMouseCaptureLost() {
+  SetThumbTrackState(CustomButton::BS_NORMAL);
+  repeater_.Stop();
+}
+
+bool BitmapScrollBar::OnKeyPressed(const KeyEvent& event) {
+  ScrollAmount amount = SCROLL_NONE;
+  switch (event.key_code()) {
+    case ui::VKEY_UP:
+      if (!IsHorizontal())
+        amount = SCROLL_PREV_LINE;
+      break;
+    case ui::VKEY_DOWN:
+      if (!IsHorizontal())
+        amount = SCROLL_NEXT_LINE;
+      break;
+    case ui::VKEY_LEFT:
+      if (IsHorizontal())
+        amount = SCROLL_PREV_LINE;
+      break;
+    case ui::VKEY_RIGHT:
+      if (IsHorizontal())
+        amount = SCROLL_NEXT_LINE;
+      break;
+    case ui::VKEY_PRIOR:
+      amount = SCROLL_PREV_PAGE;
+      break;
+    case ui::VKEY_NEXT:
+      amount = SCROLL_NEXT_PAGE;
+      break;
+    case ui::VKEY_HOME:
+      amount = SCROLL_START;
+      break;
+    case ui::VKEY_END:
+      amount = SCROLL_END;
+      break;
+  }
+  if (amount != SCROLL_NONE) {
+    ScrollByAmount(amount);
+    return true;
+  }
+  return false;
+}
+
+bool BitmapScrollBar::OnMouseWheel(const MouseWheelEvent& event) {
+  ScrollByContentsOffset(event.offset());
+  return true;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
-// BitmapScrollBar, View implementation:
+// BitmapScrollBar, ContextMenuController implementation:
 
-void BitmapScrollBar::OnPaint(gfx::Canvas* canvas) {
-  // Paint the track.
-  gfx::Rect track_bounds = GetTrackBounds();
-  canvas->TileImageInt(*images_[THUMB_TRACK][GetThumbTrackState()],
-                       track_bounds.x(), track_bounds.y(),
-                       track_bounds.width(), track_bounds.height());
+enum ScrollBarContextMenuCommands {
+  ScrollBarContextMenuCommand_ScrollHere = 1,
+  ScrollBarContextMenuCommand_ScrollStart,
+  ScrollBarContextMenuCommand_ScrollEnd,
+  ScrollBarContextMenuCommand_ScrollPageUp,
+  ScrollBarContextMenuCommand_ScrollPageDown,
+  ScrollBarContextMenuCommand_ScrollPrev,
+  ScrollBarContextMenuCommand_ScrollNext
+};
+
+void BitmapScrollBar::ShowContextMenuForView(View* source,
+                                             const gfx::Point& p,
+                                             bool is_mouse_gesture) {
+  Widget* widget = GetWidget();
+  gfx::Rect widget_bounds = widget->GetWindowScreenBounds();
+  gfx::Point temp_pt(p.x() - widget_bounds.x(), p.y() - widget_bounds.y());
+  View::ConvertPointFromWidget(this, &temp_pt);
+  context_menu_mouse_position_ = IsHorizontal() ? temp_pt.x() : temp_pt.y();
+
+  scoped_ptr<Menu> menu(
+      Menu::Create(this, Menu::TOPLEFT, GetWidget()->GetNativeView()));
+  menu->AppendDelegateMenuItem(ScrollBarContextMenuCommand_ScrollHere);
+  menu->AppendSeparator();
+  menu->AppendDelegateMenuItem(ScrollBarContextMenuCommand_ScrollStart);
+  menu->AppendDelegateMenuItem(ScrollBarContextMenuCommand_ScrollEnd);
+  menu->AppendSeparator();
+  menu->AppendDelegateMenuItem(ScrollBarContextMenuCommand_ScrollPageUp);
+  menu->AppendDelegateMenuItem(ScrollBarContextMenuCommand_ScrollPageDown);
+  menu->AppendSeparator();
+  menu->AppendDelegateMenuItem(ScrollBarContextMenuCommand_ScrollPrev);
+  menu->AppendDelegateMenuItem(ScrollBarContextMenuCommand_ScrollNext);
+  menu->RunMenuAt(p.x(), p.y());
 }
 
 ///////////////////////////////////////////////////////////////////////////////
+// BitmapScrollBar, Menu::Delegate implementation:
+
+std::wstring BitmapScrollBar::GetLabel(int id) const {
+  int ids_value = 0;
+  switch (id) {
+    case ScrollBarContextMenuCommand_ScrollHere:
+      ids_value = IDS_APP_SCROLLBAR_CXMENU_SCROLLHERE;
+      break;
+    case ScrollBarContextMenuCommand_ScrollStart:
+      ids_value = IsHorizontal() ? IDS_APP_SCROLLBAR_CXMENU_SCROLLLEFTEDGE
+                                 : IDS_APP_SCROLLBAR_CXMENU_SCROLLHOME;
+      break;
+    case ScrollBarContextMenuCommand_ScrollEnd:
+      ids_value = IsHorizontal() ? IDS_APP_SCROLLBAR_CXMENU_SCROLLRIGHTEDGE
+                                 : IDS_APP_SCROLLBAR_CXMENU_SCROLLEND;
+      break;
+    case ScrollBarContextMenuCommand_ScrollPageUp:
+      ids_value = IDS_APP_SCROLLBAR_CXMENU_SCROLLPAGEUP;
+      break;
+    case ScrollBarContextMenuCommand_ScrollPageDown:
+      ids_value = IDS_APP_SCROLLBAR_CXMENU_SCROLLPAGEDOWN;
+      break;
+    case ScrollBarContextMenuCommand_ScrollPrev:
+      ids_value = IsHorizontal() ? IDS_APP_SCROLLBAR_CXMENU_SCROLLLEFT
+                                 : IDS_APP_SCROLLBAR_CXMENU_SCROLLUP;
+      break;
+    case ScrollBarContextMenuCommand_ScrollNext:
+      ids_value = IsHorizontal() ? IDS_APP_SCROLLBAR_CXMENU_SCROLLRIGHT
+                                 : IDS_APP_SCROLLBAR_CXMENU_SCROLLDOWN;
+      break;
+    default:
+      NOTREACHED() << "Invalid BitmapScrollBar Context Menu command!";
+  }
+
+  return ids_value ? UTF16ToWide(l10n_util::GetStringUTF16(ids_value)) : L"";
+}
+
+bool BitmapScrollBar::IsCommandEnabled(int id) const {
+  switch (id) {
+    case ScrollBarContextMenuCommand_ScrollPageUp:
+    case ScrollBarContextMenuCommand_ScrollPageDown:
+      return !IsHorizontal();
+  }
+  return true;
+}
+
+void BitmapScrollBar::ExecuteCommand(int id) {
+  switch (id) {
+    case ScrollBarContextMenuCommand_ScrollHere:
+      ScrollToThumbPosition(context_menu_mouse_position_, true);
+      break;
+    case ScrollBarContextMenuCommand_ScrollStart:
+      ScrollByAmount(SCROLL_START);
+      break;
+    case ScrollBarContextMenuCommand_ScrollEnd:
+      ScrollByAmount(SCROLL_END);
+      break;
+    case ScrollBarContextMenuCommand_ScrollPageUp:
+      ScrollByAmount(SCROLL_PREV_PAGE);
+      break;
+    case ScrollBarContextMenuCommand_ScrollPageDown:
+      ScrollByAmount(SCROLL_NEXT_PAGE);
+      break;
+    case ScrollBarContextMenuCommand_ScrollPrev:
+      ScrollByAmount(SCROLL_PREV_LINE);
+      break;
+    case ScrollBarContextMenuCommand_ScrollNext:
+      ScrollByAmount(SCROLL_NEXT_LINE);
+      break;
+  }
+}
+
+///////////////////////////////////////////////////////////////////////////////
 // BitmapScrollBar, ButtonListener implementation:
 
 void BitmapScrollBar::ButtonPressed(Button* sender, const views::Event& event) {
@@ -306,4 +649,87 @@
   }
 }
 
+///////////////////////////////////////////////////////////////////////////////
+// BitmapScrollBar, ScrollBar implementation:
+
+void BitmapScrollBar::Update(int viewport_size, int content_size,
+                             int contents_scroll_offset) {
+  ScrollBar::Update(viewport_size, content_size, contents_scroll_offset);
+
+  // Make sure contents_size is always > 0 to avoid divide by zero errors in
+  // calculations throughout this code.
+  contents_size_ = std::max(1, content_size);
+
+  if (content_size < 0)
+    content_size = 0;
+  if (contents_scroll_offset < 0)
+    contents_scroll_offset = 0;
+  if (contents_scroll_offset > content_size)
+    contents_scroll_offset = content_size;
+
+  // Thumb Height and Thumb Pos.
+  // The height of the thumb is the ratio of the Viewport height to the
+  // content size multiplied by the height of the thumb track.
+  double ratio = static_cast<double>(viewport_size) / contents_size_;
+  int thumb_size = static_cast<int>(ratio * GetTrackSize());
+  thumb_->SetSize(thumb_size);
+
+  int thumb_position = CalculateThumbPosition(contents_scroll_offset);
+  thumb_->SetPosition(thumb_position);
+}
+
+int BitmapScrollBar::GetLayoutSize() const {
+  gfx::Size prefsize = prev_button_->GetPreferredSize();
+  return IsHorizontal() ? prefsize.height() : prefsize.width();
+}
+
+int BitmapScrollBar::GetPosition() const {
+  return thumb_->GetPosition();
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// BitmapScrollBar, View implementation:
+
+void BitmapScrollBar::OnPaint(gfx::Canvas* canvas) {
+  // Paint the track.
+  gfx::Rect track_bounds = GetTrackBounds();
+  canvas->TileImageInt(*images_[THUMB_TRACK][thumb_track_state_],
+                       track_bounds.x(), track_bounds.y(),
+                       track_bounds.width(), track_bounds.height());
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// BitmapScrollBar, private:
+
+void BitmapScrollBar::TrackClicked() {
+  if (last_scroll_amount_ != SCROLL_NONE)
+    ScrollByAmount(last_scroll_amount_);
+}
+
+void BitmapScrollBar::ScrollContentsToOffset() {
+  GetController()->ScrollToPosition(this, contents_scroll_offset_);
+  thumb_->SetPosition(CalculateThumbPosition(contents_scroll_offset_));
+}
+
+int BitmapScrollBar::GetTrackSize() const {
+  gfx::Rect track_bounds = GetTrackBounds();
+  return IsHorizontal() ? track_bounds.width() : track_bounds.height();
+}
+
+int BitmapScrollBar::CalculateThumbPosition(int contents_scroll_offset) const {
+  return (contents_scroll_offset * GetTrackSize()) / contents_size_;
+}
+
+int BitmapScrollBar::CalculateContentsOffset(int thumb_position,
+                                             bool scroll_to_middle) const {
+  if (scroll_to_middle)
+    thumb_position = thumb_position - (thumb_->GetSize() / 2);
+  return (thumb_position * contents_size_) / GetTrackSize();
+}
+
+void BitmapScrollBar::SetThumbTrackState(CustomButton::ButtonState state) {
+  thumb_track_state_ = state;
+  SchedulePaint();
+}
+
 }  // namespace views