Create new target to hold gpu test code, enable direct testing of GrEffects in GM.

R=robertphillips@google.com, jvanverth@google.com, egdaniel@google.com

Author: bsalomon@google.com

Review URL: https://chromiumcodereview.appspot.com/23352003

git-svn-id: http://skia.googlecode.com/svn/trunk@10866 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/gmmain.cpp b/gm/gmmain.cpp
index 32ad413..ca266e3 100644
--- a/gm/gmmain.cpp
+++ b/gm/gmmain.cpp
@@ -1559,8 +1559,8 @@
             errorsForAllConfigs.add(kIntentionallySkipped_ErrorType);
             continue;
         }
-        if ((gmFlags & GM::kSkipGPU_Flag) &&
-            kGPU_Backend == config.fBackend) {
+        if (((gmFlags & GM::kSkipGPU_Flag) && kGPU_Backend == config.fBackend) ||
+            ((gmFlags & GM::kGPUOnly_Flag) && kGPU_Backend != config.fBackend)) {
             gmmain.RecordTestResults(kIntentionallySkipped_ErrorType, shortNamePlusConfig,
                                      renderModeDescriptor);
             errorsForAllConfigs.add(kIntentionallySkipped_ErrorType);