Distinguish common and unique names for skiaperf.com.

Turns out we tack on the size post-facto in ResultsWriter::bench(), so the only
place we need getUniqueName() to differ from getName() is SKPBench.

BUG=skia:
R=jcgregorio@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/552303004
diff --git a/bench/SKPBench.h b/bench/SKPBench.h
index 9cc9192..0b0e008 100644
--- a/bench/SKPBench.h
+++ b/bench/SKPBench.h
@@ -21,6 +21,7 @@
 
 protected:
     virtual const char* onGetName() SK_OVERRIDE;
+    virtual const char* onGetUniqueName() SK_OVERRIDE;
     virtual bool isSuitableFor(Backend backend) SK_OVERRIDE;
     virtual void onDraw(const int loops, SkCanvas* canvas) SK_OVERRIDE;
     virtual SkIPoint onGetSize() SK_OVERRIDE;
@@ -30,6 +31,7 @@
     const SkIRect fClip;
     const SkScalar fScale;
     SkString fName;
+    SkString fUniqueName;
 
     typedef Benchmark INHERITED;
 };