Get the linen background painting during elastic scrolling

We weren't setting the location of the resource bundle correctly in the
renderer process. It turns out base::mac::OuterBundle() returns the helper
app's bundle in the renderer process. So now we have MainApplicationBundle() to
give us the bundle of the main app.

brightray/common/mac/main_application_bundle.h

@@ -0,0 +1,20 @@
+#ifndef BRIGHTRAY_COMMON_MAC_MAIN_APPLICATION_BUNDLE_H_
+#define BRIGHTRAY_COMMON_MAC_MAIN_APPLICATION_BUNDLE_H_
+
+@class NSBundle;
+
+namespace base {
+class FilePath;
+}
+
+namespace brightray {
+
+// The "main" application bundle is the outermost bundle for this logical application. E.g., if you
+// have MyApp.app and MyApp.app/Contents/Frameworks/MyApp Helper.app, the main application bundle is
+// MyApp.app, no matter which executable is currently running.
+NSBundle* MainApplicationBundle();
+base::FilePath MainApplicationBundlePath();
+
+}
+
+#endif

brightray/common/mac/main_application_bundle.mm

@@ -0,0 +1,42 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright (c) 2013 Adam Roben <adam@roben.org>. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE-CHROMIUM file.
+
+#import "common/mac/main_application_bundle.h"
+
+#import "base/files/file_path.h"
+#import "base/mac/foundation_util.h"
+#import "base/path_service.h"
+
+namespace brightray {
+
+base::FilePath MainApplicationBundlePath() {
+  // Start out with the path to the running executable.
+  base::FilePath path;
+  PathService::Get(base::FILE_EXE, &path);
+
+  // Up to Contents.
+  if (base::mac::IsBackgroundOnlyProcess()) {
+    // The running executable is the helper. Go up five steps:
+    // Contents/Frameworks/Helper.app/Contents/MacOS/Helper
+    // ^ to here                                     ^ from here
+    path = path.DirName().DirName().DirName().DirName().DirName();
+  } else {
+    // One step up to MacOS, another to Contents.
+    path = path.DirName().DirName();
+  }
+  DCHECK_EQ(path.BaseName().value(), "Contents");
+
+  // Up one more level to the .app.
+  path = path.DirName();
+  DCHECK_EQ(path.BaseName().Extension(), ".app");
+
+  return path;
+}
+
+NSBundle* MainApplicationBundle() {
+  return [NSBundle bundleWithPath:base::mac::FilePathToNSString(MainApplicationBundlePath())];
+}
+
+}