Reland 204146 - Introduces a new scrollbar for message_center.

The new one overlaps with the scroll contents.

TBR=sadrul@chromium.org
BUG=239559
R=mukai@chromium.org

Review URL: https://chromiumcodereview.appspot.com/16670002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@205545 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 230 insertions, 8 deletions

diff --git a/ui/message_center/views/message_center_view.cc b/ui/message_center/views/message_center_view.cc
index 8e87df5..2d72653 100644
--- a/ui/message_center/views/message_center_view.cc
+++ b/ui/message_center/views/message_center_view.cc
@@ -31,7 +31,7 @@
 #include "ui/views/controls/button/label_button.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/scroll_view.h"
-#include "ui/views/controls/scrollbar/kennedy_scroll_bar.h"
+#include "ui/views/controls/scrollbar/overlay_scroll_bar.h"
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/layout/grid_layout.h"
 #include "ui/views/painter.h"
@@ -304,7 +304,7 @@ BoundedScrollView::BoundedScrollView(int min_height, int max_height)
   if (IsRichNotificationEnabled()) {
     set_background(views::Background::CreateSolidBackground(
         kMessageCenterBackgroundColor));
-    SetVerticalScrollBar(new views::KennedyScrollBar(false));
+    SetVerticalScrollBar(new views::OverlayScrollBar(false));
   }
 }
 
diff --git a/ui/message_center/views/notifier_settings_view.cc b/ui/message_center/views/notifier_settings_view.cc
index eeef62d..ba8c50b 100644
--- a/ui/message_center/views/notifier_settings_view.cc
+++ b/ui/message_center/views/notifier_settings_view.cc
@@ -20,7 +20,7 @@
 #include "ui/views/controls/image_view.h"
 #include "ui/views/controls/label.h"
 #include "ui/views/controls/scroll_view.h"
-#include "ui/views/controls/scrollbar/kennedy_scroll_bar.h"
+#include "ui/views/controls/scrollbar/overlay_scroll_bar.h"
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/widget/widget.h"
 
@@ -290,7 +290,7 @@ NotifierSettingsView::NotifierSettingsView(
 
   scroller_ = new views::ScrollView();
   scroller_->set_border(new Separator());
-  scroller_->SetVerticalScrollBar(new views::KennedyScrollBar(false));
+  scroller_->SetVerticalScrollBar(new views::OverlayScrollBar(false));
   AddChildView(scroller_);
 
   views::View* contents_view = new views::View();
diff --git a/ui/views/controls/scroll_view.cc b/ui/views/controls/scroll_view.cc
index 3659c35..11ffc02 100644
--- a/ui/views/controls/scroll_view.cc
+++ b/ui/views/controls/scroll_view.cc
@@ -117,6 +117,8 @@ ScrollView::ScrollView()
       vert_sb_(new NativeScrollBar(false)),
       resize_corner_(NULL),
       hide_horizontal_scrollbar_(false) {
+  set_notify_enter_exit_on_child(true);
+
   AddChildView(contents_viewport_);
   AddChildView(header_viewport_);
 
@@ -252,15 +254,17 @@ void ScrollView::Layout() {
   }
 
   if (horiz_sb_required) {
+    int height_offset = horiz_sb_->GetContentOverlapSize();
     horiz_sb_->SetBounds(0,
-                         viewport_bounds.bottom(),
+                         viewport_bounds.bottom() - height_offset,
                          viewport_bounds.right(),
-                         horiz_sb_height);
+                         horiz_sb_height + height_offset);
   }
   if (vert_sb_required) {
-    vert_sb_->SetBounds(viewport_bounds.right(),
+    int width_offset = vert_sb_->GetContentOverlapSize();
+    vert_sb_->SetBounds(viewport_bounds.right() - width_offset,
                         0,
-                        vert_sb_width,
+                        vert_sb_width + width_offset,
                         viewport_bounds.bottom());
   }
   if (resize_corner_required) {
@@ -312,6 +316,20 @@ bool ScrollView::OnMouseWheel(const ui::MouseWheelEvent& e) {
   return processed;
 }
 
+void ScrollView::OnMouseEntered(const ui::MouseEvent& event) {
+  if (horiz_sb_)
+    horiz_sb_->OnMouseEnteredScrollView(event);
+  if (vert_sb_)
+    vert_sb_->OnMouseEnteredScrollView(event);
+}
+
+void ScrollView::OnMouseExited(const ui::MouseEvent& event) {
+  if (horiz_sb_)
+    horiz_sb_->OnMouseExitedScrollView(event);
+  if (vert_sb_)
+    vert_sb_->OnMouseExitedScrollView(event);
+}
+
 void ScrollView::OnGestureEvent(ui::GestureEvent* event) {
   // If the event happened on one of the scrollbars, then those events are
   // sent directly to the scrollbars. Otherwise, only scroll events are sent to
diff --git a/ui/views/controls/scroll_view.h b/ui/views/controls/scroll_view.h
index 857ddac..da87ffd 100644
--- a/ui/views/controls/scroll_view.h
+++ b/ui/views/controls/scroll_view.h
@@ -70,6 +70,8 @@ class VIEWS_EXPORT ScrollView : public View, public ScrollBarController {
   virtual void Layout() OVERRIDE;
   virtual bool OnKeyPressed(const ui::KeyEvent& event) OVERRIDE;
   virtual bool OnMouseWheel(const ui::MouseWheelEvent& e) OVERRIDE;
+  virtual void OnMouseEntered(const ui::MouseEvent& event) OVERRIDE;
+  virtual void OnMouseExited(const ui::MouseEvent& event) OVERRIDE;
   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
   virtual const char* GetClassName() const OVERRIDE;
 
diff --git a/ui/views/controls/scrollbar/overlay_scroll_bar.cc b/ui/views/controls/scrollbar/overlay_scroll_bar.cc
new file mode 100644
index 0000000..c7e254a
--- /dev/null
+++ b/ui/views/controls/scrollbar/overlay_scroll_bar.cc
@@ -0,0 +1,142 @@
+// Copyright 2013 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 "ui/views/controls/scrollbar/overlay_scroll_bar.h"
+
+#include "third_party/skia/include/core/SkColor.h"
+#include "third_party/skia/include/core/SkXfermode.h"
+#include "ui/gfx/canvas.h"
+#include "ui/views/background.h"
+#include "ui/views/border.h"
+#include "ui/views/controls/scrollbar/base_scroll_bar_thumb.h"
+
+namespace views {
+namespace {
+
+const int kScrollbarWidth = 10;
+const int kThumbInsetInside = 3;
+const int kThumbInsetFromEdge = 1;
+const int kThumbCornerRadius = 2;
+const int kThumbMinimumSize = kScrollbarWidth;
+const int kThumbHoverAlpha = 128;
+const int kThumbDefaultAlpha = 64;
+
+class OverlayScrollBarThumb : public BaseScrollBarThumb,
+                              public ui::AnimationDelegate {
+ public:
+  explicit OverlayScrollBarThumb(BaseScrollBar* scroll_bar);
+  virtual ~OverlayScrollBarThumb();
+
+ protected:
+  // View overrides:
+  virtual gfx::Size GetPreferredSize() OVERRIDE;
+  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
+
+  // ui::AnimationDelegate overrides:
+  virtual void AnimationProgressed(const ui::Animation* animation) OVERRIDE;
+
+ private:
+  double animation_opacity_;
+  DISALLOW_COPY_AND_ASSIGN(OverlayScrollBarThumb);
+};
+
+OverlayScrollBarThumb::OverlayScrollBarThumb(BaseScrollBar* scroll_bar)
+    : BaseScrollBarThumb(scroll_bar),
+      animation_opacity_(0.0) {
+  if (get_use_acceleration_when_possible()) {
+    // This is necessary, otherwise the thumb will be rendered below the views
+    // if those views paint to their own layers.
+    SetPaintToLayer(true);
+    SetFillsBoundsOpaquely(false);
+  }
+}
+
+OverlayScrollBarThumb::~OverlayScrollBarThumb() {
+}
+
+gfx::Size OverlayScrollBarThumb::GetPreferredSize() {
+  return gfx::Size(kThumbMinimumSize, kThumbMinimumSize);
+}
+
+void OverlayScrollBarThumb::OnPaint(gfx::Canvas* canvas) {
+  gfx::Rect local_bounds(GetLocalBounds());
+  SkPaint paint;
+  int alpha = (GetState() == CustomButton::STATE_HOVERED ||
+               GetState() == CustomButton::STATE_PRESSED) ?
+      kThumbHoverAlpha : kThumbDefaultAlpha;
+  alpha *= animation_opacity_;
+  paint.setStyle(SkPaint::kFill_Style);
+  paint.setColor(SkColorSetARGB(alpha, 0, 0, 0));
+  canvas->DrawRoundRect(local_bounds, kThumbCornerRadius, paint);
+}
+
+void OverlayScrollBarThumb::AnimationProgressed(
+    const ui::Animation* animation) {
+  animation_opacity_ = animation->GetCurrentValue();
+  SchedulePaint();
+}
+
+}  // namespace
+
+OverlayScrollBar::OverlayScrollBar(bool horizontal)
+    : BaseScrollBar(horizontal, new OverlayScrollBarThumb(this)),
+      animation_(static_cast<OverlayScrollBarThumb*>(GetThumb())) {
+  set_notify_enter_exit_on_child(true);
+}
+
+OverlayScrollBar::~OverlayScrollBar() {
+}
+
+gfx::Rect OverlayScrollBar::GetTrackBounds() const {
+  gfx::Rect local_bounds(GetLocalBounds());
+  if (IsHorizontal()) {
+    local_bounds.Inset(kThumbInsetFromEdge, kThumbInsetInside,
+                       kThumbInsetFromEdge, kThumbInsetFromEdge);
+  } else {
+    local_bounds.Inset(kThumbInsetInside, kThumbInsetFromEdge,
+                       kThumbInsetFromEdge, kThumbInsetFromEdge);
+  }
+  gfx::Size track_size = local_bounds.size();
+  track_size.SetToMax(GetThumb()->size());
+  local_bounds.set_size(track_size);
+  return local_bounds;
+}
+
+int OverlayScrollBar::GetLayoutSize() const {
+  return 0;
+}
+
+int OverlayScrollBar::GetContentOverlapSize() const {
+  return kScrollbarWidth;
+}
+
+void OverlayScrollBar::OnMouseEnteredScrollView(const ui::MouseEvent& event) {
+  animation_.Show();
+}
+
+void OverlayScrollBar::OnMouseExitedScrollView(const ui::MouseEvent& event) {
+  animation_.Hide();
+}
+
+gfx::Size OverlayScrollBar::GetPreferredSize() {
+  return gfx::Size();
+}
+
+void OverlayScrollBar::Layout() {
+  gfx::Rect thumb_bounds = GetTrackBounds();
+  BaseScrollBarThumb* thumb = GetThumb();
+  if (IsHorizontal()) {
+    thumb_bounds.set_x(thumb->x());
+    thumb_bounds.set_width(thumb->width());
+  } else {
+    thumb_bounds.set_y(thumb->y());
+    thumb_bounds.set_height(thumb->height());
+  }
+  thumb->SetBoundsRect(thumb_bounds);
+}
+
+void OverlayScrollBar::OnPaint(gfx::Canvas* canvas) {
+}
+
+}  // namespace views
diff --git a/ui/views/controls/scrollbar/overlay_scroll_bar.h b/ui/views/controls/scrollbar/overlay_scroll_bar.h
new file mode 100644
index 0000000..043f5f7
--- /dev/null
+++ b/ui/views/controls/scrollbar/overlay_scroll_bar.h
@@ -0,0 +1,41 @@
+// Copyright 2013 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.
+
+#ifndef UI_VIEWS_CONTROLS_SCROLLBAR_OVERLAY_SCROLL_BAR_H_
+#define UI_VIEWS_CONTROLS_SCROLLBAR_OVERLAY_SCROLL_BAR_H_
+
+#include "ui/base/animation/slide_animation.h"
+#include "ui/views/controls/scrollbar/base_scroll_bar.h"
+
+namespace views {
+
+// The transparent scrollbar which overlays its contents.
+class VIEWS_EXPORT OverlayScrollBar : public BaseScrollBar {
+ public:
+  explicit OverlayScrollBar(bool horizontal);
+  virtual ~OverlayScrollBar();
+
+ protected:
+  // BaseScrollBar overrides:
+  virtual gfx::Rect GetTrackBounds() const OVERRIDE;
+
+  // ScrollBar overrides:
+  virtual int GetLayoutSize() const OVERRIDE;
+  virtual int GetContentOverlapSize() const OVERRIDE;
+  virtual void OnMouseEnteredScrollView(const ui::MouseEvent& event) OVERRIDE;
+  virtual void OnMouseExitedScrollView(const ui::MouseEvent& event) OVERRIDE;
+
+  // View overrides:
+  virtual gfx::Size GetPreferredSize() OVERRIDE;
+  virtual void Layout() OVERRIDE;
+  virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
+
+ private:
+  ui::SlideAnimation animation_;
+  DISALLOW_COPY_AND_ASSIGN(OverlayScrollBar);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_CONTROLS_SCROLLBAR_OVERLAY_SCROLL_BAR_H_
diff --git a/ui/views/controls/scrollbar/scroll_bar.cc b/ui/views/controls/scrollbar/scroll_bar.cc
index 7719d86..5374d32 100644
--- a/ui/views/controls/scrollbar/scroll_bar.cc
+++ b/ui/views/controls/scrollbar/scroll_bar.cc
@@ -31,6 +31,16 @@ int ScrollBar::GetMinPosition() const {
   return 0;
 }
 
+int ScrollBar::GetContentOverlapSize() const {
+  return 0;
+}
+
+void ScrollBar::OnMouseEnteredScrollView(const ui::MouseEvent& event) {
+}
+
+void ScrollBar::OnMouseExitedScrollView(const ui::MouseEvent& event) {
+}
+
 ScrollBar::ScrollBar(bool is_horiz)
     : is_horiz_(is_horiz),
       controller_(NULL),
diff --git a/ui/views/controls/scrollbar/scroll_bar.h b/ui/views/controls/scrollbar/scroll_bar.h
index 5b534d6..aa3800e 100644
--- a/ui/views/controls/scrollbar/scroll_bar.h
+++ b/ui/views/controls/scrollbar/scroll_bar.h
@@ -86,6 +86,13 @@ class VIEWS_EXPORT ScrollBar : public View {
   // is the height for a horizontal scrollbar.
   virtual int GetLayoutSize() const = 0;
 
+  // Get the width or height for this scrollbar which overlaps with the content.
+  // Default is 0.
+  virtual int GetContentOverlapSize() const;
+
+  virtual void OnMouseEnteredScrollView(const ui::MouseEvent& event);
+  virtual void OnMouseExitedScrollView(const ui::MouseEvent& event);
+
  protected:
   // Create new scrollbar, either horizontal or vertical. These are protected
   // since you need to be creating either a NativeScrollBar or a
diff --git a/ui/views/views.gyp b/ui/views/views.gyp
index 3acfcc6..3155021 100644
--- a/ui/views/views.gyp
+++ b/ui/views/views.gyp
@@ -188,6 +188,8 @@
         'controls/scrollbar/native_scroll_bar_wrapper.h',
         'controls/scrollbar/native_scroll_bar.cc',
         'controls/scrollbar/native_scroll_bar.h',
+        'controls/scrollbar/overlay_scroll_bar.cc',
+        'controls/scrollbar/overlay_scroll_bar.h',
         'controls/scrollbar/scroll_bar.cc',
         'controls/scrollbar/scroll_bar.h',
         'controls/separator.cc',