Make appending default precision be controled by GLSL

src/gpu/glsl/GrGLSL.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLSL_DEFINED
 #define GrGLSL_DEFINED
 
 #include "GrTypesPriv.h"
 #include "SkString.h"
 
+class GrGLSLCaps;
+
 // Limited set of GLSL versions we build shaders for. Caller should round
 // down the GLSL version to one of these enums.
 enum GrGLSLGeneration {
     /**
      * Desktop GLSL 1.10 and ES2 shading language (based on desktop GLSL 1.20)
      */
     k110_GrGLSLGeneration,
     /**
      * Desktop GLSL 1.30
      */
@@ skipping 25 matching lines @@
 inline const char* GrGLSLTexture2DFunctionName(GrSLType coordType, GrGLSLGeneration glslGen) {
     if (kVec2f_GrSLType == coordType) {
         return glslGen >= k130_GrGLSLGeneration ? "texture" : "texture2D";
     } else {
         SkASSERT(kVec3f_GrSLType == coordType);
         return glslGen >= k130_GrGLSLGeneration ? "textureProj" : "texture2DProj";
     }
 }
 
 /**
+ * Adds a line of GLSL code to declare the default precision for float types.
+ */
+void GrGLSLAppendDefaultFloatPrecisionDeclaration(GrSLPrecision,
+                                                  const GrGLSLCaps& glslCaps,
+                                                  SkString* out);
+
+/**
  * Converts a GrSLType to a string containing the name of the equivalent GLSL type.
  */
 static inline const char* GrGLSLTypeString(GrSLType t) {
     switch (t) {
         case kVoid_GrSLType:
             return "void";
         case kFloat_GrSLType:
             return "float";
         case kVec2f_GrSLType:
             return "vec2";
@@ skipping 248 matching lines @@
 
 /**
  * Does an inplace mul, *=, of vec4VarName by mulFactor.
  * A semicolon is added after the assignment.
  */
 void GrGLSLMulVarBy4f(SkString* outAppend, const char* vec4VarName, const GrGLSLExpr4& mulFactor);
 
 #include "GrGLSL_impl.h"
 
 #endif