compositor: Fix compositor_unittests build on Linux.

This makes compositor_unittests compiles on Linux.

Although running it doesn't work yet because we return NULL in
TestCompositorHost::Create() and it expects something different than NULL.

R=sky@chromium.org

Review URL: http://codereview.chromium.org/7996005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@102391 0039d316-1c4b-4281-b951-d872f2087c98

ui/gfx/compositor/compositor.gyp

@@ -97,6 +97,7 @@
         'layer_unittest.cc',
         'run_all_unittests.cc',
         'test_compositor_host.h',
+        'test_compositor_host_linux.cc',
         'test_compositor_host_win.cc',
         'test_suite.cc',
         'test_suite.h',

ui/gfx/compositor/layer_unittest.cc

@@ -34,7 +34,7 @@ class TestLayerDelegate : public LayerDelegate {
     canvas->FillRectInt(colors_.at(color_index_), 0, 0,
                         contents.width(),
                         contents.height());
-    color_index_ = ++color_index_ % colors_.size();
+    color_index_ = (color_index_ + 1) % static_cast<int>(colors_.size());
   }
 
  private:

ui/gfx/compositor/test_compositor_host_linux.cc

+// 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.
+
+#include "ui/gfx/compositor/test_compositor_host.h"
+
+namespace ui {
+
+// static
+TestCompositorHost* TestCompositorHost::Create(const gfx::Rect& bounds) {
+  return NULL;
+}
+
+}  // namespace ui