Infer sampler precision from pixel config

src/gpu/GrCaps.cpp

Index: src/gpu/GrCaps.cpp
diff --git a/src/gpu/GrCaps.cpp b/src/gpu/GrCaps.cpp
index 41f5b9b391357d8a0e5940799df10b75f8927fc5..e2253dbef5e97f24e00642dfc7d206176037442b 100644
--- a/src/gpu/GrCaps.cpp
+++ b/src/gpu/GrCaps.cpp
@@ -69,9 +69,34 @@ SkString GrShaderCaps::dump() const {
         }
     }
 
+    r.append("Effective Float Precisions:\n");
+
+    for (int s = 0; s < kGrShaderTypeCount; ++s) {
+        GrShaderType shaderType = static_cast<GrShaderType>(s);
+        r.appendf("\t%s:  ", shader_type_to_string(shaderType));
+        for (int p = kGrSLPrecisionCount - 1 ; p >= 0; --p) {
+            GrSLPrecision precision = static_cast<GrSLPrecision>(p);
+            r.appendf("%s=%s", precision_to_string(precision),
+                      precision_to_string(fEffectiveFloatPrecisions[s][p]));
+            r.append(p + 1 < kGrSLPrecisionCount ? "  " : "\n");
+        }
+    }
+
     return r;
 }
 
+void GrShaderCaps::initEffectiveFloatPrecisionTable() {
+    for (int s = 0; s < kGrShaderTypeCount; ++s) {
+        const PrecisionInfo* info = fFloatPrecisions[s];
+        GrSLPrecision* p = fEffectiveFloatPrecisions[s];
+        p[kHigh_GrSLPrecision] = kHigh_GrSLPrecision;
+        p[kMedium_GrSLPrecision] = info[kHigh_GrSLPrecision] == info[kMedium_GrSLPrecision] ?
+                                       kHigh_GrSLPrecision : kMedium_GrSLPrecision;
+        p[kLow_GrSLPrecision] = info[kMedium_GrSLPrecision] == info[kLow_GrSLPrecision] ?
+                                    p[kMedium_GrSLPrecision] : kLow_GrSLPrecision;
+    }
+}
+
 void GrShaderCaps::applyOptionsOverrides(const GrContextOptions& options) {
     fDualSourceBlendingSupport = fDualSourceBlendingSupport && !options.fSuppressDualSourceBlending;
     this->onApplyOptionsOverrides(options);