Widget::ShouldUseNativeFrame is now meaningful on Linux.

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

 // Copyright (c) 2012 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 "chrome/browser/ui/views/tabs/tab_strip.h"
 
 #if defined(OS_WIN)
 #include <windowsx.h>
 #endif
 
@@ skipping 52 matching lines @@
 #endif
 
 using base::UserMetricsAction;
 using ui::DropTargetEvent;
 
 namespace {
 
 static const int kTabStripAnimationVSlop = 40;
 // Inactive tabs in a native frame are slightly transparent.
 static const int kNativeFrameInactiveTabAlpha = 200;
+#if defined(OS_WIN)
 // If there are multiple tabs selected then make non-selected inactive tabs
 // even more transparent.
 static const int kNativeFrameInactiveTabAlphaMultiSelection = 150;

[sky, 2014/02/03 21:53:03]

Rename this to better match other naming.

[Matt Giuca, 2014/02/05 23:25:31]

Done.

+#endif
 
 // Alpha applied to all elements save the selected tabs.
 static const int kInactiveTabAndNewTabButtonAlphaAsh = 230;
 static const int kInactiveTabAndNewTabButtonAlpha = 255;
 
 // Inverse ratio of the width of a tab edge to the width of the tab. When
 // hovering over the left or right edge of a tab, the drop indicator will
 // point between tabs.
 static const int kTabEdgeRatioInverse = 4;
 
@@ skipping 240 matching lines @@
                               gfx::Path* path) const OVERRIDE;
 #if defined(OS_WIN)
   virtual void OnMouseReleased(const ui::MouseEvent& event) OVERRIDE;
 #endif
   virtual void OnPaint(gfx::Canvas* canvas) OVERRIDE;
 
   // Overridden from ui::EventHandler:
   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
 
  private:
-  bool ShouldUseNativeFrame() const;
+  // Returns true on Windows if the Glass styling is being used.
+  // This implies that the tab strip overlaps a native window frame.
+  bool UsingWindowsGlass() const;
   gfx::ImageSkia GetBackgroundImage(views::CustomButton::ButtonState state,
                                     ui::ScaleFactor scale_factor) const;
   gfx::ImageSkia GetImageForState(views::CustomButton::ButtonState state,
                                   ui::ScaleFactor scale_factor) const;
   gfx::ImageSkia GetImageForScale(ui::ScaleFactor scale_factor) const;
 
   // Tab strip that contains this button.
   TabStrip* tab_strip_;
 
   // The offset used to paint the background image.
@@ skipping 73 matching lines @@
   canvas->DrawImageInt(image, 0, height() - image.height());
 }
 
 void NewTabButton::OnGestureEvent(ui::GestureEvent* event) {
   // Consume all gesture events here so that the parent (Tab) does not
   // start consuming gestures.
   views::ImageButton::OnGestureEvent(event);
   event->SetHandled();
 }
 
-bool NewTabButton::ShouldUseNativeFrame() const {
+bool NewTabButton::UsingWindowsGlass() const {
+#if defined(OS_WIN)
   return GetWidget() &&
     GetWidget()->GetTopLevelWidget()->ShouldUseNativeFrame();
+#endif
+return false;
 }
 
 gfx::ImageSkia NewTabButton::GetBackgroundImage(
     views::CustomButton::ButtonState state,
     ui::ScaleFactor scale_factor) const {
   int background_id = 0;
-  if (ShouldUseNativeFrame()) {
+  if (UsingWindowsGlass()) {
     background_id = IDR_THEME_TAB_BACKGROUND_V;
   } else if (tab_strip_->controller()->IsIncognito()) {
     background_id = IDR_THEME_TAB_BACKGROUND_INCOGNITO;
 #if defined(OS_WIN)
   } else if (win8::IsSingleWindowMetroMode()) {
     background_id = IDR_THEME_TAB_BACKGROUND_V;
 #endif
   } else {
     background_id = IDR_THEME_TAB_BACKGROUND;
   }
 
   int alpha = 0;
   switch (state) {
     case views::CustomButton::STATE_NORMAL:
     case views::CustomButton::STATE_HOVERED:
-      alpha = ShouldUseNativeFrame() ? kNativeFrameInactiveTabAlpha : 255;
+      alpha = UsingWindowsGlass() ? kNativeFrameInactiveTabAlpha : 255;
       break;
     case views::CustomButton::STATE_PRESSED:
       alpha = 145;
       break;
     default:
       NOTREACHED();
       break;
   }
 
   gfx::ImageSkia* mask =
@@ skipping 50 matching lines @@
         IDR_NEWTAB_BUTTON_P : IDR_NEWTAB_BUTTON;
   gfx::ImageSkia* overlay = GetThemeProvider()->GetImageSkiaNamed(overlay_id);
 
   gfx::Canvas canvas(
       gfx::Size(overlay->width(), overlay->height()),
       ui::GetImageScale(scale_factor),
       false);
   canvas.DrawImageInt(GetBackgroundImage(state, scale_factor), 0, 0);
 
   // Draw the button border with a slight alpha.
   const int kNativeFrameOverlayAlpha = 178;

[sky, 2014/02/03 21:53:03]

rename these too.

[Matt Giuca, 2014/02/05 23:25:31]

Done.

   const int kOpaqueFrameOverlayAlpha = 230;
-  uint8 alpha = ShouldUseNativeFrame() ?
+  uint8 alpha = UsingWindowsGlass() ?
       kNativeFrameOverlayAlpha : kOpaqueFrameOverlayAlpha;
   canvas.DrawImageInt(*overlay, 0, 0, alpha);
 
   return gfx::ImageSkia(canvas.ExtractImageRep());
 }
 
 gfx::ImageSkia NewTabButton::GetImageForScale(
     ui::ScaleFactor scale_factor) const {
   if (!hover_animation_->is_animating())
     return GetImageForState(state(), scale_factor);
@@ skipping 786 matching lines @@
     }
 
     for (int i = tab_count() - 1; i > active_tab_index; --i) {
       Tab* tab = tab_at(i);
       tab->Paint(canvas);
     }
   }
   if (inactive_tab_alpha < 255)
     canvas->Restore();
 
+#if defined(OS_WIN)

[sky, 2014/02/03 21:53:03]

I would rather move the ifdef to a function with a descriptive name. Maybe
something like ShouldFadeUnselectedTabs().

[Matt Giuca, 2014/02/05 23:25:31]

Done.

   if (GetWidget()->ShouldUseNativeFrame()) {
+    // On Windows, a native frame implies Glass.
     // Make sure non-active tabs are somewhat transparent.
     SkPaint paint;
     // If there are multiple tabs selected, fade non-selected tabs more to make
     // the selected tabs more noticable.
     int alpha = selected_tab_count > 1 ?
         kNativeFrameInactiveTabAlphaMultiSelection :
         kNativeFrameInactiveTabAlpha;
     paint.setColor(SkColorSetARGB(alpha, 255, 255, 255));
     paint.setXfermodeMode(SkXfermode::kDstIn_Mode);
     paint.setStyle(SkPaint::kFill_Style);
     // The tabstrip area overlaps the toolbar area by 2 px.
     canvas->DrawRect(gfx::Rect(0, 0, width(), height() - 2), paint);
   }
+#endif
 
   // Now selected but not active. We don't want these dimmed if using native
   // frame, so they're painted after initial pass.
   for (size_t i = 0; i < selected_tabs.size(); ++i)
     selected_tabs[i]->Paint(canvas);
 
   // Next comes the active tab.
   if (active_tab && !is_dragging)
     active_tab->Paint(canvas);
 
@@ skipping 1414 matching lines @@
 #if defined(USE_AURA)
   return chrome::GetHostDesktopTypeForNativeView(
       GetWidget()->GetNativeView()) == chrome::HOST_DESKTOP_TYPE_ASH;
 #else
   if (ui::GetDisplayLayout() != ui::LAYOUT_TOUCH)
     return false;
 #endif
 
   return true;
 }