Make local coords be highp in default geometry processor

This fixes some regressions on the Nexus 10 that were introduced when the device coordinate feature was removed from GrCoordTransform.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2987

Change-Id: Ib0286b1e056d6d8f875a45beee8b0eda85dc1382
Reviewed-on: https://skia-review.googlesource.com/2987
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/GrDefaultGeoProcFactory.cpp b/src/gpu/GrDefaultGeoProcFactory.cpp
index 497f6b7..7d89f27 100644
--- a/src/gpu/GrDefaultGeoProcFactory.cpp
+++ b/src/gpu/GrDefaultGeoProcFactory.cpp
@@ -222,7 +222,8 @@
             fInColor = &this->addVertexAttrib("inColor", kVec4ub_GrVertexAttribType);
         }
         if (hasExplicitLocalCoords) {
-            fInLocalCoords = &this->addVertexAttrib("inLocalCoord", kVec2f_GrVertexAttribType);
+            fInLocalCoords = &this->addVertexAttrib("inLocalCoord", kVec2f_GrVertexAttribType,
+                                                    kHigh_GrSLPrecision);
             this->setHasExplicitLocalCoords();
         }
         if (hasCoverage) {