Adjusted split view tab's bounds/padding in vertical tab

browser/ui/views/tabs/brave_tab.cc

@@ -54,6 +54,11 @@ std::u16string BraveTab::GetTooltipText(const gfx::Point& p) const {
   return Tab::GetTooltipText(p);
 }
 
+void BraveTab::UpdateBorder() {
+  // In vertical tab, different border is used based on split view state.
+  SetBorder(views::CreateEmptyBorder(tab_style_views()->GetContentsInsets()));
+}
+
 int BraveTab::GetWidthOfLargestSelectableRegion() const {
   // Assume the entire region except the area that alert indicator/close buttons
   // occupied is available for click-to-select.

browser/ui/views/tabs/brave_tab.h

@@ -24,6 +24,7 @@ class BraveTab : public Tab {
 
   // Tab:
   std::u16string GetTooltipText(const gfx::Point& p) const override;
+  void UpdateBorder() override;
 
   // Overridden because we moved alert button to left side in the tab whereas
   // upstream put it on right side. Need to consider this change for calculating

browser/ui/views/tabs/brave_tab_container.cc

@@ -470,7 +470,6 @@ std::optional<BrowserRootView::DropIndex> BraveTabContainer::GetDropIndex(
         continue;
       }
 
-
       const bool is_tab_pinned = tab->data().pinned;
 
       // When dropping text or links onto pinned tabs, we need to take the
@@ -601,10 +600,12 @@ void BraveTabContainer::HandleDragExited() {
 }
 
 void BraveTabContainer::OnTileTabs(const TabTile& tile) {
+  UpdateTabsBorderInTile(tile);
   SchedulePaint();
 }
 
 void BraveTabContainer::OnDidBreakTile(const TabTile& tile) {
+  UpdateTabsBorderInTile(tile);
   SchedulePaint();
 }
 
@@ -757,5 +758,31 @@ void BraveTabContainer::SetDropArrow(
   drop_arrow_->SetWindowBounds(drop_bounds);
 }
 
+bool BraveTabContainer::IsPinnedTabContainer() const {
+  return tabs_view_model_.view_size() > 0 && tabs_view_model_.view_at(0)->data().pinned;
+}
+
+void BraveTabContainer::UpdateTabsBorderInTile(const TabTile& tile) {
+  auto* tab_strip_model = tab_slot_controller_->GetBrowser()->tab_strip_model();
+  const int offset =
+      IsPinnedTabContainer() ? 0 : tab_strip_model->IndexOfFirstNonPinnedTab();
+
+  auto tab1_index = tab_strip_model->GetIndexOfTab(tile.first) - offset;
+  auto tab2_index = tab_strip_model->GetIndexOfTab(tile.second) - offset;
+
+  if (!controller_->IsValidModelIndex(tab1_index) ||
+      !controller_->IsValidModelIndex(tab2_index)) {
+    // In case the tiled tab is not in this container, this can happen.
+    // For instance, this container is for pinned tabs but tabs in the tile
+    // are unpinned.
+    return;
+  }
+
+  auto* tab1 = GetTabAtModelIndex(tab1_index);
+  auto* tab2 = GetTabAtModelIndex(tab2_index);
+  tab1->UpdateBorder();
+  tab2->UpdateBorder();
+}
+
 BEGIN_METADATA(BraveTabContainer)
 END_METADATA

browser/ui/views/tabs/brave_tab_container.h

@@ -121,6 +121,9 @@ class BraveTabContainer : public TabContainerImpl,
                           bool drop_in_group,
                           bool* is_beneath);
 
+  bool IsPinnedTabContainer() const;
+  void UpdateTabsBorderInTile(const TabTile& tile);
+
   base::flat_set<Tab*> closing_tabs_;
 
   raw_ptr<TabDragContextBase> drag_context_;

browser/ui/views/tabs/brave_tab_style_views.inc.cc

@@ -13,6 +13,8 @@ namespace {
 
 using tabs::features::HorizontalTabsUpdateEnabled;
 
+constexpr auto kPaddingForVerticalTabInTile = 4;
+
 // Returns a value indicating if the browser frame view is "condensed", i.e.
 // that its frame border is somehow collapsed, as in fullscreen or when
 // maximized, or in Linux when caption buttons and the title bar are not
@@ -215,13 +217,13 @@ SkPath BraveVerticalTabStyle::GetPath(
     }
   }
 
-  if (IsTabTiled(tab()) && path_type != TabStyle::PathType::kHitTest) {
+  if (!is_pinned && IsTabTiled(tab()) && path_type != TabStyle::PathType::kHitTest) {
     if (ShouldShowVerticalTabs()) {
-      constexpr auto kPaddingForVerticalTab = 4;
-      tab_top += scale * kPaddingForVerticalTab;
-      tab_bottom -= scale * kPaddingForVerticalTab;
-      tab_left += scale * kPaddingForVerticalTab;
-      tab_right -= scale * kPaddingForVerticalTab;
+      tab()->controller()->IsFirstTabInTile(tab())
+          ? tab_top += scale* kPaddingForVerticalTabInTile
+          : tab_bottom -= scale * kPaddingForVerticalTabInTile;
+      tab_left += scale * kPaddingForVerticalTabInTile;
+      tab_right -= scale * kPaddingForVerticalTabInTile;
     } else {
       // Give 2 dip more padding when tab is in tile.
       constexpr auto kPaddingForHorizontalTab = 2;
@@ -251,20 +253,30 @@ SkPath BraveVerticalTabStyle::GetPath(
 }
 
 gfx::Insets BraveVerticalTabStyle::GetContentsInsets() const {
-  if (!HorizontalTabsUpdateEnabled()) {
-    return BraveTabStyleViews::GetContentsInsets();
+  const bool is_pinned = tab()->data().pinned;
+  auto insets = tab_style()->GetContentsInsets();
+
+  if (!is_pinned && ShouldShowVerticalTabs() && IsTabTiled(tab())) {
+    const bool is_first_tab = tab()->controller()->IsFirstTabInTile(tab());
+    return insets + gfx::Insets::TLBR(
+                        is_first_tab ? kPaddingForVerticalTabInTile : 0, 0,
+                        is_first_tab ? 0 : kPaddingForVerticalTabInTile, 0);
   }
 
-  // Ignore any stroke widths when determining the horizontal contents insets.
-  // To make contents vertically align evenly regardless of overlap in non
-  // vertical tab, use it as bottom inset in a tab as it's hidden by
-  // overlapping.
-  const int bottom_inset = ShouldShowVerticalTabs()
-                               ? 0
-                               : GetLayoutConstant(TABSTRIP_TOOLBAR_OVERLAP);
+  if (HorizontalTabsUpdateEnabled()) {
+    // Ignore any stroke widths when determining the horizontal contents insets.
+    // To make contents vertically align evenly regardless of overlap in non
+    // vertical tab, use it as bottom inset in a tab as it's hidden by
+    // overlapping.
+    return insets +
+           gfx::Insets::TLBR(0, 0,
+                             ShouldShowVerticalTabs()
+                                 ? 0
+                                 : GetLayoutConstant(TABSTRIP_TOOLBAR_OVERLAP),
+                             0);
+  }
 
-  return tab_style()->GetContentsInsets() +
-         gfx::Insets::TLBR(0, 0, bottom_inset, 0);
+  return BraveTabStyleViews::GetContentsInsets();
 }
 
 TabStyle::SeparatorBounds BraveVerticalTabStyle::GetSeparatorBounds(

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

@@ -13,6 +13,7 @@ class BraveTab;
   kMinimumContentsWidthForCloseButtons = 55; \
   friend class ::BraveTabTest;               \
   friend class ::BraveTab;                   \
+  virtual void UpdateBorder() {}             \
   static constexpr int kMinimumContentsWidthForCloseButtons_UnUsed
 
 #define GetWidthOfLargestSelectableRegion \