Hide the tab's close-x in Refresh's single-tab mode.

This patch refactors the single tab mode to be tracked by the tabstrip,
and enabled/disabled by BrowserNonClientFrameView when appropriate. The
tabstrip uses that mode flag to force the close-x for the active tab to
be invisible.

Bug: 841643
Change-Id: I0c8713e5190af935d665e7d10f984db8624b4ab0
Reviewed-on: https://chromium-review.googlesource.com/1068214
Commit-Queue: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563109}

chrome/browser/ui/views/frame/browser_non_client_frame_view.cc

@@ -119,6 +119,13 @@ void BrowserNonClientFrameView::ChildPreferredSizeChanged(views::View* child) {
   }
 }
 
+void BrowserNonClientFrameView::OnThemeChanged() {
+  // Adding or removing a frame image will change whether single tab mode is
+  // available.
+  if (MD::IsRefreshUi() && browser_view()->IsTabStripVisible())
+    browser_view()->tabstrip()->SingleTabModeChanged();
+}
+
 void BrowserNonClientFrameView::VisibilityChanged(views::View* starting_from,
                                                   bool is_visible) {
   // UpdateTaskbarDecoration() calls DrawTaskbarDecoration(), but that does
@@ -130,15 +137,15 @@ void BrowserNonClientFrameView::VisibilityChanged(views::View* starting_from,
 }
 
 void BrowserNonClientFrameView::OnTabAdded(int index) {
-  if (MD::IsRefreshUi() && browser_view()->tabstrip()->tab_count() == 2) {
-    // We are exiting single-tab mode and need to repaint the frame.
+  if (IsSingleTabModeAvailable()) {
+    // We may be exiting single-tab mode and need to repaint the frame.
     SchedulePaint();
   }
 }
 
 void BrowserNonClientFrameView::OnTabRemoved(int index) {
-  if (MD::IsRefreshUi() && browser_view()->tabstrip()->tab_count() == 1) {
-    // We are entering single-tab mode and need to repaint the frame.
+  if (IsSingleTabModeAvailable()) {
+    // We may be entering single-tab mode and need to repaint the frame.
     SchedulePaint();
   }
 }
@@ -147,13 +154,16 @@ bool BrowserNonClientFrameView::ShouldPaintAsThemed() const {
   return browser_view_->IsBrowserTypeNormal();
 }
 
-bool BrowserNonClientFrameView::ShouldPaintAsSingleTabMode() const {
-  // Single-tab mode is only available in Refresh. The special color we use for
+bool BrowserNonClientFrameView::IsSingleTabModeAvailable() const {
+  // Single-tab mode is only available in Refresh. The special color we use
   // won't be visible if there's a frame image, but since it's used to determine
   // constrast of other UI elements, the theme color should be used instead.
-  return MD::IsRefreshUi() && GetFrameImage().isNull() &&
-         browser_view()->IsTabStripVisible() &&
-         browser_view()->tabstrip()->tab_count() == 1;
+  return MD::IsRefreshUi() && GetFrameImage().isNull();
+}
+
+bool BrowserNonClientFrameView::ShouldPaintAsSingleTabMode() const {
+  return browser_view()->IsTabStripVisible() &&
+         browser_view()->tabstrip()->SingleTabMode();
 }
 
 SkColor BrowserNonClientFrameView::GetFrameColor(bool active) const {

chrome/browser/ui/views/frame/browser_non_client_frame_view.h

@@ -90,8 +90,13 @@ class BrowserNonClientFrameView : public views::NonClientFrameView,
   // https://crbug.com/820485.
   virtual int GetTabStripLeftInset() const;
 
+  // Whether the special painting mode for one tab is allowed, regardless of how
+  // many tabs there are right now.
+  bool IsSingleTabModeAvailable() const;
+
   // views::NonClientFrameView:
   void ChildPreferredSizeChanged(views::View* child) override;
+  void OnThemeChanged() override;
   void VisibilityChanged(views::View* starting_from, bool is_visible) override;
 
   // TabStripObserver:
@@ -104,7 +109,7 @@ class BrowserNonClientFrameView : public views::NonClientFrameView,
   // not.
   virtual bool ShouldPaintAsThemed() const;
 
-  // Whether the frame should be painted with a special mode for one tab.
+  // Whether the frame should be painted with the special mode for one tab.
   bool ShouldPaintAsSingleTabMode() const;
 
   // Compute aspects of the frame needed to paint the frame background.

chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc

@@ -346,6 +346,10 @@ void BrowserTabStripController::StackedLayoutMaybeChanged() {
                                                tabstrip_->stacked_layout());
 }
 
+bool BrowserTabStripController::IsSingleTabModeAvailable() {
+  return browser_view_->frame()->GetFrameView()->IsSingleTabModeAvailable();
+}
+
 void BrowserTabStripController::OnStartedDraggingTabs() {
   if (!immersive_reveal_lock_.get()) {
     // The top-of-window views should be revealed while the user is dragging

chrome/browser/ui/views/tabs/browser_tab_strip_controller.h

@@ -70,6 +70,7 @@ class BrowserTabStripController : public TabStripController,
   void CreateNewTabWithLocation(const base::string16& loc) override;
   bool IsIncognito() override;
   void StackedLayoutMaybeChanged() override;
+  bool IsSingleTabModeAvailable() override;
   void OnStartedDraggingTabs() override;
   void OnStoppedDraggingTabs() override;
   SkColor GetToolbarTopSeparatorColor() const override;

chrome/browser/ui/views/tabs/fake_base_tab_strip_controller.cc

@@ -128,6 +128,10 @@ bool FakeBaseTabStripController::IsIncognito() {
 void FakeBaseTabStripController::StackedLayoutMaybeChanged() {
 }
 
+bool FakeBaseTabStripController::IsSingleTabModeAvailable() {
+  return false;
+}
+
 void FakeBaseTabStripController::OnStartedDraggingTabs() {
 }
 

chrome/browser/ui/views/tabs/fake_base_tab_strip_controller.h

@@ -47,6 +47,7 @@ class FakeBaseTabStripController : public TabStripController {
   void CreateNewTabWithLocation(const base::string16& loc) override;
   bool IsIncognito() override;
   void StackedLayoutMaybeChanged() override;
+  bool IsSingleTabModeAvailable() override;
   void OnStartedDraggingTabs() override;
   void OnStoppedDraggingTabs() override;
   SkColor GetToolbarTopSeparatorColor() const override;

chrome/browser/ui/views/tabs/tab.cc

@@ -1343,7 +1343,7 @@ void Tab::PaintSeparator(gfx::Canvas* canvas, SkColor inactive_color) {
 
 void Tab::UpdateIconVisibility() {
   center_favicon_ = false;
-  showing_icon_ = showing_alert_indicator_ = showing_close_button_ = false;
+  showing_icon_ = showing_alert_indicator_ = false;
   extra_padding_before_content_ = false;
 
   const gfx::Size min_size(GetMinimumInactiveSize());
@@ -1371,10 +1371,6 @@ void Tab::UpdateIconVisibility() {
   const bool has_alert_icon =
       (alert_indicator_button_ ? alert_indicator_button_->showing_alert_state()
                                : data().alert_state) != TabAlertState::NONE;
-  const bool hide_inactive_close_button =
-      controller_->ShouldHideCloseButtonForInactiveTabs();
-  const bool show_close_button_on_hover =
-      controller_->ShouldShowCloseButtonOnHover();
 
   if (is_pinned) {
     // When the tab is pinned, we can show one of the two icons. Alert icon
@@ -1382,10 +1378,10 @@ void Tab::UpdateIconVisibility() {
     // tab is pinned.
     showing_alert_indicator_ = has_alert_icon;
     showing_icon_ = has_favicon && !has_alert_icon;
+    showing_close_button_ = false;
   } else {
+    showing_close_button_ = !controller_->ShouldHideCloseButtonForTab(this);
     if (is_active) {
-      // The close button is always visible for an active tab.
-      showing_close_button_ = true;
       available_width -= close_button_width;
 
       showing_alert_indicator_ =
@@ -1412,18 +1408,17 @@ void Tab::UpdateIconVisibility() {
       if (!showing_icon_ || !showing_alert_indicator_)
         extra_padding = 0;
 
-      // For an inactive tab, the close button will be visible only when
-      // it is not forced to hide and the total width can accomodate all 3
-      // icons. When favicon or alert button is not visible, its space
-      // will be occupied by the title of this tab.
+      // Show the close button if it's allowed to show on hover, even if it's
+      // forced to be hidden normally.
+      showing_close_button_ |= controller_->ShouldShowCloseButtonOnHover() &&
+                               hover_controller_.ShouldDraw();
+      // Always hide the close button if the total width can't accomodate all 3
+      // icons. When favicon or alert button is not visible, its space will be
+      // occupied by the title of this tab.
       int title_width =
           (!showing_icon_ + !showing_alert_indicator_) * favicon_width;
-      if ((!hide_inactive_close_button ||
-           (show_close_button_on_hover && hover_controller_.ShouldDraw())) &&
-          (title_width + close_button_width + extra_padding <=
-           available_width)) {
-        showing_close_button_ = true;
-      }
+      if (title_width + close_button_width + extra_padding > available_width)
+        showing_close_button_ = false;
 
       // If no other controls are visible, show favicon even though we
       // don't have enough space. We'll clip the favicon in PaintChildren().

chrome/browser/ui/views/tabs/tab.h

@@ -60,6 +60,27 @@ class Tab : public gfx::AnimationDelegate,
   Tab(TabController* controller, gfx::AnimationContainer* container);
   ~Tab() override;
 
+  // views::View:
+  void ViewHierarchyChanged(
+      const ViewHierarchyChangedDetails& details) override;
+  void OnPaint(gfx::Canvas* canvas) override;
+  void PaintChildren(const views::PaintInfo& info) override;
+  void Layout() override;
+  void OnThemeChanged() override;
+  const char* GetClassName() const override;
+  bool GetTooltipText(const gfx::Point& p,
+                      base::string16* tooltip) const override;
+  bool GetTooltipTextOrigin(const gfx::Point& p,
+                            gfx::Point* origin) const override;
+  bool OnMousePressed(const ui::MouseEvent& event) override;
+  bool OnMouseDragged(const ui::MouseEvent& event) override;
+  void OnMouseReleased(const ui::MouseEvent& event) override;
+  void OnMouseCaptureLost() override;
+  void OnMouseEntered(const ui::MouseEvent& event) override;
+  void OnMouseMoved(const ui::MouseEvent& event) override;
+  void OnMouseExited(const ui::MouseEvent& event) override;
+  void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
+
   TabController* controller() const { return controller_; }
 
   // Used to set/check whether this Tab is being animated closed.
@@ -133,10 +154,6 @@ class Tab : public gfx::AnimationDelegate,
   // user to click to select/activate the tab.
   int GetWidthOfLargestSelectableRegion() const;
 
-  // Called when stacked layout changes and the close button may need to
-  // be updated.
-  void HideCloseButtonForInactiveTabsChanged() { Layout(); }
-
   // Returns the minimum possible size of a single unselected Tab.
   static gfx::Size GetMinimumInactiveSize();
 
@@ -187,27 +204,6 @@ class Tab : public gfx::AnimationDelegate,
   // views::MaskedTargeterDelegate:
   bool GetHitTestMask(gfx::Path* mask) const override;
 
-  // views::View:
-  void ViewHierarchyChanged(
-      const ViewHierarchyChangedDetails& details) override;
-  void OnPaint(gfx::Canvas* canvas) override;
-  void PaintChildren(const views::PaintInfo& info) override;
-  void Layout() override;
-  void OnThemeChanged() override;
-  const char* GetClassName() const override;
-  bool GetTooltipText(const gfx::Point& p,
-                      base::string16* tooltip) const override;
-  bool GetTooltipTextOrigin(const gfx::Point& p,
-                            gfx::Point* origin) const override;
-  bool OnMousePressed(const ui::MouseEvent& event) override;
-  bool OnMouseDragged(const ui::MouseEvent& event) override;
-  void OnMouseReleased(const ui::MouseEvent& event) override;
-  void OnMouseCaptureLost() override;
-  void OnMouseEntered(const ui::MouseEvent& event) override;
-  void OnMouseMoved(const ui::MouseEvent& event) override;
-  void OnMouseExited(const ui::MouseEvent& event) override;
-  void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
-
   // ui::EventHandler:
   void OnGestureEvent(ui::GestureEvent* event) override;
 

chrome/browser/ui/views/tabs/tab_controller.h

@@ -39,9 +39,8 @@ class TabController {
   // Returns true if multiple selection is supported.
   virtual bool SupportsMultipleSelection() = 0;
 
-  // Returns true if the close buttons of the inactive tabs are forced to be
-  // hidden.
-  virtual bool ShouldHideCloseButtonForInactiveTabs() = 0;
+  // Returns true if the close button for the given tab is forced to be hidden.
+  virtual bool ShouldHideCloseButtonForTab(Tab* tab) const = 0;
 
   // Returns true if the close button on an inactive tab should be shown on
   // mouse hover. This is predicated on ShouldHideCloseButtonForInactiveTabs()

chrome/browser/ui/views/tabs/tab_strip.cc

@@ -409,7 +409,11 @@ void TabStrip::SetStackedLayout(bool stacked_layout) {
   }
 
   for (int i = 0; i < tab_count(); ++i)
-    tab_at(i)->HideCloseButtonForInactiveTabsChanged();
+    tab_at(i)->Layout();
+}
+
+bool TabStrip::SingleTabMode() const {
+  return controller_->IsSingleTabModeAvailable() && tab_count() == 1;
 }
 
 bool TabStrip::SizeTabButtonToTopOfTabStrip() {
@@ -429,6 +433,8 @@ void TabStrip::StopAllHighlighting() {
 }
 
 void TabStrip::AddTabAt(int model_index, TabRendererData data, bool is_active) {
+  const bool was_single_tab_mode = SingleTabMode();
+
   Tab* tab = new Tab(this, animation_container_.get());
   AddChildView(tab);
   const bool pinned = data.pinned;
@@ -456,6 +462,9 @@ void TabStrip::AddTabAt(int model_index, TabRendererData data, bool is_active) {
 
   SwapLayoutIfNecessary();
 
+  if (was_single_tab_mode)
+    SingleTabModeChanged();
+
   for (TabStripObserver& observer : observers_)
     observer.OnTabAdded(model_index);
 
@@ -525,6 +534,9 @@ void TabStrip::RemoveTabAt(content::WebContents* contents, int model_index) {
   for (TabStripObserver& observer : observers_)
     observer.OnTabRemoved(model_index);
 
+  if (SingleTabMode())
+    SingleTabModeChanged();
+
   // Stop dragging when a new tab is removed and dragging a window. Doing
   // otherwise results in a confusing state if the user attempts to reattach. We
   // could allow this and make TabDragController update itself during the
@@ -781,7 +793,9 @@ bool TabStrip::SupportsMultipleSelection() {
   return touch_layout_ == nullptr;
 }
 
-bool TabStrip::ShouldHideCloseButtonForInactiveTabs() {
+bool TabStrip::ShouldHideCloseButtonForTab(Tab* tab) const {
+  if (tab->IsActive())
+    return SingleTabMode();
   return touch_layout_ != nullptr || MD::IsRefreshUi();
 }
 
@@ -2406,6 +2420,12 @@ void TabStrip::SetResetToShrinkOnExit(bool value) {
     RemoveMessageLoopObserver();
 }
 
+void TabStrip::SingleTabModeChanged() {
+  const int active_tab_index = controller_->GetActiveIndex();
+  if (IsValidModelIndex(active_tab_index))
+    tab_at(active_tab_index)->Layout();
+}
+
 void TabStrip::ButtonPressed(views::Button* sender, const ui::Event& event) {
   if (sender == new_tab_button_) {
     base::RecordAction(UserMetricsAction("NewTab_Button"));

chrome/browser/ui/views/tabs/tab_strip.h

@@ -124,6 +124,13 @@ class TabStrip : public views::View,
   // Sets |stacked_layout_| and animates if necessary.
   void SetStackedLayout(bool stacked_layout);
 
+  // Whether the special painting mode for a single tab is enabled. This is only
+  // true if both the mode is available and we have exactly one tab.
+  bool SingleTabMode() const;
+
+  // Called when the value of SingleTabMode() changes.
+  void SingleTabModeChanged();
+
   // Returns the bounds of the new tab button.
   gfx::Rect new_tab_button_bounds() const { return new_tab_button_bounds_; }
 
@@ -219,7 +226,7 @@ class TabStrip : public views::View,
   // TabController overrides:
   const ui::ListSelectionModel& GetSelectionModel() const override;
   bool SupportsMultipleSelection() override;
-  bool ShouldHideCloseButtonForInactiveTabs() override;
+  bool ShouldHideCloseButtonForTab(Tab* tab) const override;
   bool ShouldShowCloseButtonOnHover() override;
   bool MaySetClip() override;
   void SelectTab(Tab* tab) override;

chrome/browser/ui/views/tabs/tab_strip_controller.h

@@ -102,6 +102,9 @@ class TabStripController {
   // Invoked if the stacked layout (on or off) might have changed.
   virtual void StackedLayoutMaybeChanged() = 0;
 
+  // Whether the special painting mode for one tab is allowed.
+  virtual bool IsSingleTabModeAvailable() = 0;
+
   // Notifies controller that the user started dragging this tabstrip's tabs.
   virtual void OnStartedDraggingTabs() = 0;
 

chrome/browser/ui/views/tabs/tab_unittest.cc

@@ -38,9 +38,7 @@ class FakeTabController : public TabController {
     return selection_model_;
   }
   bool SupportsMultipleSelection() override { return false; }
-  bool ShouldHideCloseButtonForInactiveTabs() override {
-    return false;
-  }
+  bool ShouldHideCloseButtonForTab(Tab* tab) const override { return false; }
   bool ShouldShowCloseButtonOnHover() override { return false; }
   bool MaySetClip() override { return false; }
   void SelectTab(Tab* tab) override {}