Refactor OpaqueBrowserFrameView; reduce uses of kUseSystemTitleBar.

chrome/browser/ui/views/frame/opaque_browser_frame_view_layout.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 "chrome/browser/ui/views/frame/opaque_browser_frame_view_layout.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/ui/views/avatar_label.h"
 #include "chrome/browser/ui/views/avatar_menu_button.h"
@@ skipping 250 matching lines @@
     int width,
     int height) const {
   int top_height = NonClientTopBorderHeight(false);
   int border_thickness = NonClientBorderThickness();
   return gfx::Rect(border_thickness, top_height,
                    std::max(0, width - (2 * border_thickness)),
                    std::max(0, height - top_height - border_thickness));
 }
 
 bool OpaqueBrowserFrameViewLayout::IsTitleBarCondensed() const {
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
-  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kUseSystemTitleBar))
-    return true;
-#endif
-
-  return delegate_->IsMaximized();
+  // If there are no caption buttons, there is no need to have an uncondensed
+  // title bar. If the window is maximized, the title bar is condensed
+  // regardless of whether there are caption buttons.
+  return !delegate_->ShouldShowCaptionButtons() || delegate_->IsMaximized();

[Matt Giuca, 2014/01/24 05:55:11]

Detailed logic as to why this does not change any behaviour:

On Linux, this is equivalent to:
  kUseSystemTitleBar || (UnityIsRunning && IsMaximized) || IsMaximized
= kUseSystemTitleBar || IsMaximized

On Windows 8, this is equivalent to:
  IsSingleWindowMetroMode || IsMaximized
= IsMaximized

On other platforms, this is equivalent to:
  IsMaximized

So this refactor gives the same logic as before (but with the bonus of
offloading the decision about the kUseSystemTitleBar switch to
OpaqueBrowserFrameView).

I believe this has good future-proof semantics. The rationale for NOT condensing
the title bar is because you want extra room to display the caption buttons, so
I believe the new logic captures the intent of condensing the title bar as well
as the existing behaviour.

 }
 
 ///////////////////////////////////////////////////////////////////////////////
 // OpaqueBrowserFrameView, private:
 
 bool OpaqueBrowserFrameViewLayout::ShouldAvatarBeOnRight() const {
   // The avatar should be shown either on the end of the left or the beginning
   // of the right depending on which side has fewer buttons.
   return trailing_buttons_.size() < leading_buttons_.size();
 }
@@ skipping 415 matching lines @@
 
 void OpaqueBrowserFrameViewLayout::ViewAdded(views::View* host,
                                              views::View* view) {
   SetView(view->id(), view);
 }
 
 void OpaqueBrowserFrameViewLayout::ViewRemoved(views::View* host,
                                                views::View* view) {
   SetView(view->id(), NULL);
 }