Really fix valgrind issue

TBR=
BUG=skia:

Review URL: https://codereview.chromium.org/795123002
diff --git a/src/gpu/GrDrawState.cpp b/src/gpu/GrDrawState.cpp
index 465c10c..faf8cd4 100644
--- a/src/gpu/GrDrawState.cpp
+++ b/src/gpu/GrDrawState.cpp
@@ -86,6 +86,8 @@
 
     fColorProcInfoValid = that.fColorProcInfoValid;
     fCoverageProcInfoValid = that.fCoverageProcInfoValid;
+    fColorCache = that.fColorCache;
+    fCoverageCache = that.fCoverageCache;
     if (fColorProcInfoValid) {
         fColorProcInfo = that.fColorProcInfo;
     }