aura: Have aura and aura_demo build and run without gtk on linux.

ui/base/x/x11_util.h

 // Copyright (c) 2011 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.
 
 #ifndef UI_BASE_X_X11_UTIL_H_
 #define UI_BASE_X_X11_UTIL_H_
 #pragma once
 
 // This file declares utility functions for X11 (Linux only).
 //
 // These functions do not require the Xlib headers to be included (which is why
 // we use a void* for Visual*). The Xlib headers are highly polluting so we try
 // hard to limit their spread into the rest of the code.
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "ui/base/ui_export.h"
 
 typedef unsigned long Atom;
-typedef struct _GdkDrawable GdkWindow;
-typedef struct _GtkWidget GtkWidget;
-typedef struct _GtkWindow GtkWindow;
 typedef unsigned long XID;
 typedef unsigned long XSharedMemoryId;  // ShmSeg in the X headers.
 typedef struct _XDisplay Display;
 
+#if defined(TOOLKIT_USES_GTK)
+typedef struct _GdkDrawable GdkWindow;
+typedef struct _GtkWidget GtkWidget;
+typedef struct _GtkWindow GtkWindow;
+#endif
+
 namespace gfx {
 class Rect;
 }
 
 namespace ui {
 
 // These functions use the GDK default display and this /must/ be called from
 // the UI thread. Thus, they don't support multiple displays.
 
 // These functions cache their results ---------------------------------
@@ skipping 26 matching lines @@
 int GetDefaultScreen(Display* display);
 
 // These functions do not cache their results --------------------------
 
 // Get the X window id for the default root window
 UI_EXPORT XID GetX11RootWindow();
 
 // Returns the user's current desktop.
 bool GetCurrentDesktop(int* desktop);
 
+#if defined(TOOLKIT_USES_GTK)
 // Get the X window id for the given GTK widget.
 UI_EXPORT XID GetX11WindowFromGtkWidget(GtkWidget* widget);
 XID GetX11WindowFromGdkWindow(GdkWindow* window);
 
 // Get the GtkWindow* wrapping a given XID, if any.
 // Returns NULL if there isn't already a GtkWindow* wrapping this XID;
 // see gdk_window_foreign_new() etc. to wrap arbitrary XIDs.
 UI_EXPORT GtkWindow* GetGtkWindowFromX11Window(XID xid);
 
 // Get a Visual from the given widget. Since we don't include the Xlib
 // headers, this is returned as a void*.
 UI_EXPORT void* GetVisualFromGtkWidget(GtkWidget* widget);
+#endif  // defined(TOOLKIT_USES_GTK)
 
 // Return the number of bits-per-pixel for a pixmap of the given depth
 UI_EXPORT int BitsPerPixelForPixmapDepth(Display* display, int depth);
 
 // Returns true if |window| is visible.
 UI_EXPORT bool IsWindowVisible(XID window);
 
 // Returns the bounds of |window|.
 UI_EXPORT bool GetWindowRect(XID window, gfx::Rect* rect);
 
@@ skipping 81 matching lines @@
 // the process if called. Use SetX11ErrorHandlers() from x11_util_internal.h
 // to set your own error handlers.
 UI_EXPORT void SetDefaultX11ErrorHandlers();
 
 // Return true if a given window is in full-screen mode.
 UI_EXPORT bool IsX11WindowFullScreen(XID window);
 
 }  // namespace ui
 
 #endif  // UI_BASE_X_X11_UTIL_H_