[md] Fixes tooltips on Linux that should not have changed

ui/views/corewm/tooltip_aura.cc

 // Copyright 2013 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 "ui/views/corewm/tooltip_aura.h"
 
 #include "base/macros.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "ui/aura/window.h"
@@ skipping 11 matching lines @@
 #include "ui/views/painter.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
 namespace {
 
 // Max visual tooltip width. If a tooltip is greater than this width, it will
 // be wrapped.
 const int kTooltipMaxWidthPixels = 400;
 
-// Corner radius of tooltip background used with Material Design.
-const float kTooltipCornerRadius = 2.f;
-
 // FIXME: get cursor offset from actual cursor size.
 const int kCursorOffsetX = 10;
 const int kCursorOffsetY = 15;
 
+// TODO(varkha): Update if native widget can be transparent on Linux.
+bool CanUseTranslucentTooltipWidget() {
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+  return false;
+#else
+  return ui::MaterialDesignController::IsModeMaterial();
+#endif
+}
+
 // Creates a widget of type TYPE_TOOLTIP
 views::Widget* CreateTooltipWidget(aura::Window* tooltip_window) {
   views::Widget* widget = new views::Widget;
   views::Widget::InitParams params;
   // For aura, since we set the type to TYPE_TOOLTIP, the widget will get
   // auto-parented to the right container.
   params.type = views::Widget::InitParams::TYPE_TOOLTIP;
   params.context = tooltip_window;
   DCHECK(params.context);
   params.keep_on_top = true;
   params.accept_events = false;
-  if (ui::MaterialDesignController::IsModeMaterial()) {
+  if (CanUseTranslucentTooltipWidget())
     params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
+  if (ui::MaterialDesignController::IsModeMaterial())
     params.shadow_type = views::Widget::InitParams::SHADOW_TYPE_NONE;
-  }
   widget->Init(params);
   return widget;
 }
 
 }  // namespace
 
 namespace views {
 namespace corewm {
 
 // TODO(oshima): Consider to use views::Label.
@@ skipping 48 matching lines @@
     render_text_->SetHorizontalAlignment(gfx::ALIGN_TO_HEAD);
     render_text_->SetText(text);
     SchedulePaint();
   }
 
   void SetForegroundColor(SkColor color) {
     render_text_->SetColor(color);
   }
 
   void SetBackgroundColor(SkColor background_color) {
+    // Corner radius of tooltip background used with Material Design.
+    const float kTooltipCornerRadius = 2.f;
     views::Background* background =
-        ui::MaterialDesignController::IsModeMaterial()
+        CanUseTranslucentTooltipWidget()
             ? views::Background::CreateBackgroundPainter(
                   true, views::Painter::CreateSolidRoundRectPainter(
                             background_color, kTooltipCornerRadius))
             : views::Background::CreateSolidBackground(background_color);
     set_background(background);
     // Force the text color to be readable when |background_color| is not
     // opaque.
     render_text_->set_subpixel_rendering_suppressed(
         SkColorGetA(background_color) != 0xFF);
   }
@@ skipping 103 matching lines @@
 }
 
 void TooltipAura::OnWidgetDestroying(views::Widget* widget) {
   DCHECK_EQ(widget_, widget);
   widget_ = NULL;
   tooltip_window_ = NULL;
 }
 
 }  // namespace corewm
 }  // namespace views