re-land of new SkSL precisions

Bug: skia:
Change-Id: Ic1deb3db2cbda6ca45f93dee99832971a36a2119
Reviewed-on: https://skia-review.googlesource.com/47841
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
diff --git a/src/gpu/GrShaderVar.h b/src/gpu/GrShaderVar.h
index 7f09f8c..5a379b9 100644
--- a/src/gpu/GrShaderVar.h
+++ b/src/gpu/GrShaderVar.h
@@ -37,13 +37,12 @@
     };
 
     /**
-     * Defaults to a non-arry float with no precision specifier, type modifier, or layout qualifier.
+     * Defaults to a non-arry half with no type modifier or layout qualifier.
      */
     GrShaderVar()
-        : fType(kFloat_GrSLType)
+        : fType(kHalf_GrSLType)
         , fTypeModifier(kNone_TypeModifier)
         , fCount(kNonArray)
-        , fPrecision(kDefault_GrSLPrecision)
         , fUseUniformFloatArrays(USE_UNIFORM_FLOAT_ARRAYS) {
     }
 
@@ -116,7 +115,7 @@
              const char* extraModifiers = nullptr,
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
-        SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeAcceptsPrecision(type));
+        SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeTemporarilyAcceptsPrecision(type));
         fType = type;
         fTypeModifier = typeModifier;
         fName = name;
@@ -140,7 +139,7 @@
              const char* extraModifiers = nullptr,
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
-        SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeAcceptsPrecision(type));
+        SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeTemporarilyAcceptsPrecision(type));
         fType = type;
         fTypeModifier = typeModifier;
         fName = name;
@@ -165,7 +164,7 @@
              const char* extraModifiers = nullptr,
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
-        SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeAcceptsPrecision(type));
+        SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeTemporarilyAcceptsPrecision(type));
         fType = type;
         fTypeModifier = typeModifier;
         fName = name;
@@ -190,7 +189,7 @@
              const char* extraModifiers = nullptr,
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
-        SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeAcceptsPrecision(type));
+        SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeTemporarilyAcceptsPrecision(type));
         fType = type;
         fTypeModifier = typeModifier;
         fName = name;