Export effects classes with SK_API.

So this works in shared_library build in chromium.

This issue was raised up in the following chromium-dev thread:
https://groups.google.com/a/chromium.org/forum/?hl=en&fromgroups=#!topic/chromium-dev/Z6qzEw8MwVY

R=epoger@google.com,tomhudson@google.com

Review URL: https://codereview.appspot.com/6601065

git-svn-id: http://skia.googlecode.com/svn/trunk@5914 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/effects/SkLayerDrawLooper.h b/include/effects/SkLayerDrawLooper.h
index d347de7..5196af0 100644
--- a/include/effects/SkLayerDrawLooper.h
+++ b/include/effects/SkLayerDrawLooper.h
@@ -1,10 +1,10 @@
-
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
+
 #ifndef SkLayerDrawLooper_DEFINED
 #define SkLayerDrawLooper_DEFINED
 
@@ -133,5 +133,4 @@
     typedef SkDrawLooper INHERITED;
 };
 
-
 #endif