Fix errors when compiling with -Wall -Werror on Android.

This CL also turns those features on by default on Android

Review URL: https://codereview.appspot.com/7313049

git-svn-id: http://skia.googlecode.com/svn/trunk@7645 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/ReadWriteAlphaTest.cpp b/tests/ReadWriteAlphaTest.cpp
index a3bf5de..7830669 100644
--- a/tests/ReadWriteAlphaTest.cpp
+++ b/tests/ReadWriteAlphaTest.cpp
@@ -7,7 +7,7 @@
  */
 
 // This test is specific to the GPU backend.
-#if SK_SUPPORT_GPU
+#if SK_SUPPORT_GPU && !defined(SK_BUILD_FOR_ANDROID)
 
 #include "Test.h"
 #include "SkGpuDevice.h"
@@ -110,9 +110,7 @@
     }
 }
 
-#ifndef SK_BUILD_FOR_ANDROID
 #include "TestClassDef.h"
 DEFINE_GPUTESTCLASS("ReadWriteAlpha", ReadWriteAlphaTestClass, ReadWriteAlphaTest)
 
 #endif
-#endif