Move frame grab handle reserved space out of the tab strip.

Change-Id: I7e1527c0dbd0fea1e7aadbea2b664d991e53dae3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2486387Reviewed-by: Charlene Yan <cyan@chromium.org>
Commit-Queue: Taylor Bergquist <tbergquist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819484}

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

@@ -44,6 +44,17 @@ std::unique_ptr<views::ImageButton> CreateScrollButton(
   scroll_button->SetInkDropMode(views::Button::InkDropMode::ON);
   return scroll_button;
 }
+
+class FrameGrabHandle : public views::View {
+ public:
+  gfx::Size GetMinimumSize() const override {
+    // Reserve some space for the frame to be grabbed by, even if the tabstrip
+    // is full.
+    // TODO(tbergquist): Define this relative to the NTB insets again.
+    return gfx::Size(42, 0);
+  }
+};
+
 }  // namespace
 
 TabStripRegionView::TabStripRegionView(std::unique_ptr<TabStrip> tab_strip) {
@@ -96,11 +107,8 @@ TabStripRegionView::TabStripRegionView(std::unique_ptr<TabStrip> tab_strip) {
                                       tab_strip_container_flex_spec);
   }
 
-  reserved_grab_handle_space_ = AddChildView(std::make_unique<views::View>());
-  // TODO(tbergquist): Give |reserved_grab_handle_space_| a minimum size. For
-  // now, this space is reserved by the tabstrip itself, and we're just using
-  // this view to eat up flex space so that |tab_search_button| can be end-
-  // aligned.
+  reserved_grab_handle_space_ =
+      AddChildView(std::make_unique<FrameGrabHandle>());
   reserved_grab_handle_space_->SetProperty(
       views::kFlexBehaviorKey,
       views::FlexSpecification(views::MinimumFlexSizeRule::kScaleToMinimum,

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

@@ -2719,13 +2719,6 @@ int TabStrip::TabToNewTabButtonSpacing() const {
   return -TabStyle::GetTabInternalPadding().right();
 }
 
-int TabStrip::FrameGrabWidth() const {
-  // The grab area is adjacent to the new tab button.  Treat the padding in the
-  // new tab button as part of the grab area.
-  constexpr int kApparentWidth = 50;
-  return kApparentWidth - new_tab_button_->GetInsets().right();
-}
-
 bool TabStrip::TitlebarBackgroundIsTransparent() const {
 #if defined(OS_WIN)
   // Windows 8+ uses transparent window contents (because the titlebar area is
@@ -2796,8 +2789,7 @@ int TabStrip::GetTabAreaWidth() const {
 }
 
 int TabStrip::GetRightSideReservedWidth() const {
-  return new_tab_button_ideal_bounds_.width() + TabToNewTabButtonSpacing() +
-         FrameGrabWidth();
+  return new_tab_button_ideal_bounds_.width() + TabToNewTabButtonSpacing();
 }
 
 const Tab* TabStrip::GetLastVisibleTab() const {

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

@@ -461,10 +461,6 @@ class TabStrip : public views::View,
   // edge of the new tab button.
   int TabToNewTabButtonSpacing() const;
 
-  // Returns the space to reserve after the tabs to guarantee the user can grab
-  // part of the window frame (to move the window with).
-  int FrameGrabWidth() const;
-
   // Returns whether the window background behind the tabstrip is transparent.
   bool TitlebarBackgroundIsTransparent() const;