GTK: First draft of using native themes, partially based on evan's CL 118358.

chrome/browser/gtk/gtk_theme_provider.h

Index: chrome/browser/gtk/gtk_theme_provider.h
diff --git a/chrome/browser/gtk/gtk_theme_provider.h b/chrome/browser/gtk/gtk_theme_provider.h
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index 0000000000000000000000000000000000000000..88f0fed590469f94caf4f06f907997c2f704255e
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+++ b/chrome/browser/gtk/gtk_theme_provider.h
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+// Copyright (c) 2009 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 CHROME_BROWSER_GTK_GTK_THEME_PROVIDER_H_
+#define CHROME_BROWSER_GTK_GTK_THEME_PROVIDER_H_
+
+#include "chrome/browser/browser_theme_provider.h"
+
+#include "skia/ext/skia_utils.h"
+
+class Profile;
+
+typedef struct _GtkStyle GtkStyle;
+typedef struct _GtkWidget GtkWidget;
+
+// Specialization of BrowserThemeProvider which supplies system colors.
+class GtkThemeProvider : public BrowserThemeProvider {
+ public:
+  GtkThemeProvider();
+  virtual ~GtkThemeProvider();
+
+  // Overridden from BrowserThemeProvider:
+  //
+  // Sets that we aren't using the system theme, then calls
+  // BrowserThemeProvider's implementation.
+  virtual void SetTheme(Extension* extension);
+  virtual void UseDefaultTheme();
+  virtual void SetNativeTheme();
+
+  // Whether we should use the GTK system theme.
+  static bool UseSystemThemeGraphics(Profile* profile);
+
+ private:
+  // Load theme data from preferences, possibly picking colors from GTK.
+  virtual void LoadThemePrefs();
+
+  // Possibly creates a theme specific version of theme_toolbar_default.
+  // (minimally acceptable version right now, which is just a fill of the bg
+  // color; this should instead invoke gtk_draw_box(...) for complex theme
+  // engines.)
+  virtual SkBitmap* LoadThemeBitmap(int id);
+
+  // Handles signal from GTK that our theme has been changed.
+  static void OnStyleSet(GtkWidget* widget,
+                         GtkStyle* previous_style,
+                         GtkThemeProvider* provider);
+
+  void LoadGtkValues();
+
+  // Sets the underlying theme colors/tints from a GTK color.
+  void SetThemeColorFromGtk(const char* id, GdkColor* color);
+  void SetThemeTintFromGtk(const char* id, GdkColor* color,
+                           const skia::HSL& default_tint);
+
+  // A GtkWidget that exists only so we can look at its properties (and take
+  // its colors).
+  GtkWidget* fake_window_;
+};
+
+#endif  // CHROME_BROWSER_GTK_GTK_THEME_PROVIDER_H_