cocoa browser: remove non-material tabstrip support

chrome/browser/ui/cocoa/tabs/tab_strip_view.mm

Index: chrome/browser/ui/cocoa/tabs/tab_strip_view.mm
diff --git a/chrome/browser/ui/cocoa/tabs/tab_strip_view.mm b/chrome/browser/ui/cocoa/tabs/tab_strip_view.mm
index 2329650aa54f457d6daf25a517b8faa527c83809..279c36d8aee7d7fd907084f509a1addea63f703b 100644
--- a/chrome/browser/ui/cocoa/tabs/tab_strip_view.mm
+++ b/chrome/browser/ui/cocoa/tabs/tab_strip_view.mm
@@ -61,28 +61,6 @@ - (void)drawBottomEdge:(NSRect)dirtyRect {
   if (!themeProvider)
     return;
 
-  if (!ui::MaterialDesignController::IsModeMaterial()) {
-    // First draw the toolbar bitmap, so that theme colors can shine through.
-    NSRect backgroundRect = [self bounds];
-    backgroundRect.size.height = 2 * [self cr_lineWidth];
-    if (NSIntersectsRect(backgroundRect, dirtyRect))
-      [self drawBackground:backgroundRect];
-
-    // Draw the border bitmap, which is partially transparent.
-    NSImage* image = themeProvider->GetNSImageNamed(IDR_TOOLBAR_SHADE_TOP);
-    NSRect borderRect = backgroundRect;
-    borderRect.size.height = [image size].height;
-    if (NSIntersectsRect(borderRect, dirtyRect)) {
-      BOOL focused = [window isMainWindow];
-      NSDrawThreePartImage(borderRect, nil, image, nil, /*vertical=*/ NO,
-                           NSCompositeSourceOver,
-                           focused ?  1.0 : tabs::kImageNoFocusAlpha,
-                           /*flipped=*/ NO);
-    }
-
-    return;
-  }
-
   NSColor* strokeColor;
   if (themeProvider->HasCustomImage(IDR_THEME_TOOLBAR) ||
       themeProvider->HasCustomColor(ThemeProperties::COLOR_TOOLBAR)) {
@@ -122,7 +100,6 @@ - (void)drawRect:(NSRect)dirtyRect {
   const ui::ThemeProvider* themeProvider = [[self window] themeProvider];
   bool hasCustomThemeImage = themeProvider &&
       themeProvider->HasCustomImage(IDR_THEME_FRAME);
-  bool isModeMaterial = ui::MaterialDesignController::IsModeMaterial();
   BOOL supportsVibrancy = [self visualEffectView] != nil;
   BOOL isMainWindow = [[self window] isMainWindow];
 
@@ -131,8 +108,7 @@ - (void)drawRect:(NSRect)dirtyRect {
   // and not being used to drag tabs between browser windows). The gray is
   // somewhat opaque for Incognito mode, very opaque for non-Incognito mode, and
   // completely opaque when the window is not active.
-  if (themeProvider && !hasCustomThemeImage && isModeMaterial &&
-      !inATabDraggingOverlayWindow_) {
+  if (themeProvider && !hasCustomThemeImage && !inATabDraggingOverlayWindow_) {
     NSColor* theColor = nil;
     if (isMainWindow) {
       if (supportsVibrancy &&
@@ -371,12 +347,9 @@ - (void)setNewTabButton:(NewTabButton*)button {
 }
 
 - (NSVisualEffectView*)visualEffectView {
-  // NSVisualEffectView is only used in Material Design, and only available on
-  // OS X 10.10 and higher.
-  if (!ui::MaterialDesignController::IsModeMaterial() ||
-      !base::mac::IsAtLeastOS10_10()) {
+  // NSVisualEffectView is only available on OS X 10.10 and higher.
+  if (!base::mac::IsAtLeastOS10_10())
     return nil;
-  }
 
   NSView* rootView = [[[self window] contentView] superview];
   Class nsVisualEffectViewClass = NSClassFromString(@"NSVisualEffectView");