Move shader precision modifier check onto GLSLCaps

src/gpu/gl/GrGLCaps.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef GrGLCaps_DEFINED
 #define GrGLCaps_DEFINED
@@ skipping 248 matching lines @@
         kLATC_LATCAlias,
         kRGTC_LATCAlias,
         k3DC_LATCAlias
     };
 
     LATCAlias latcAlias() const { return fLATCAlias; }
 
     bool rgba8888PixelsOpsAreSlow() const { return fRGBA8888PixelsOpsAreSlow; }
     bool partialFBOReadIsSlow() const { return fPartialFBOReadIsSlow; }
 
-    GrGLSLCaps* glslCaps() const { return reinterpret_cast<GrGLSLCaps*>(fShaderCaps.get()); }
+    const GrGLSLCaps* glslCaps() const { return reinterpret_cast<GrGLSLCaps*>(fShaderCaps.get()); }
 
 private:
     void init(const GrContextOptions&, const GrGLContextInfo&, const GrGLInterface*);
     bool hasPathRenderingSupport(const GrGLContextInfo&, const GrGLInterface*);
 
     /**
      * Maintains a bit per GrPixelConfig. It is used to avoid redundantly
      * performing glCheckFrameBufferStatus for the same config.
      */
     struct VerifiedColorConfigs {
@@ skipping 94 matching lines @@
                 && fType      == rhs.fType
                 && fFboFormat == rhs.fFboFormat;
         }
     };
     mutable SkTHashMap<ReadPixelsSupportedFormat, bool> fReadPixelsSupportedCache;
 
     typedef GrCaps INHERITED;
 };
 
 #endif