Make addUniform take a precision

Review URL: https://codereview.chromium.org/788733003
diff --git a/src/gpu/effects/GrConvexPolyEffect.cpp b/src/gpu/effects/GrConvexPolyEffect.cpp
index 6f93fb5..248cd17 100644
--- a/src/gpu/effects/GrConvexPolyEffect.cpp
+++ b/src/gpu/effects/GrConvexPolyEffect.cpp
@@ -118,6 +118,7 @@
     // respectively.
     fRectUniform = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                        kVec4f_GrSLType,
+                                       kDefault_GrSLPrecision,
                                        "rect",
                                        &rectName);
 
@@ -211,7 +212,8 @@
     const char *edgeArrayName;
     fEdgeUniform = builder->addUniformArray(GrGLProgramBuilder::kFragment_Visibility,
                                             kVec3f_GrSLType,
-                                            "edges",
+                                             kDefault_GrSLPrecision,
+                                             "edges",
                                             cpe.getEdgeCount(),
                                             &edgeArrayName);
     GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();