Push isEqual/onIsEqual down from GrProcessor to subclasses.

R=joshualitt@google.com

Review URL: https://codereview.chromium.org/654273002
diff --git a/tests/GLProgramsTest.cpp b/tests/GLProgramsTest.cpp
index cf3d90c..16e4a1c 100644
--- a/tests/GLProgramsTest.cpp
+++ b/tests/GLProgramsTest.cpp
@@ -48,7 +48,7 @@
 
 private:
     BigKeyProcessor() { }
-    virtual bool onIsEqual(const GrProcessor&) const SK_OVERRIDE { return true; }
+    virtual bool onIsEqual(const GrFragmentProcessor&) const SK_OVERRIDE { return true; }
     virtual void onComputeInvariantOutput(InvariantOutput* inout) const SK_OVERRIDE { }
 
     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;