Initial version of external_oes texture support and unit test

src/gpu/glsl/GrGLSLCaps.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 GrGLSLCaps_DEFINED
 #define GrGLSLCaps_DEFINED
@@ skipping 84 matching lines @@
     }
 
     // This returns the name of an extension that must be enabled in the shader, if such a thing is
     // required in order to use a secondary output in the shader. This returns a nullptr if no such
     // extension is required. However, the return value of this function does not say whether dual
     // source blending is supported.
     const char* secondaryOutputExtensionString() const {
         return fSecondaryOutputExtensionString;
     }
 
+    const char* externalTextureExtensionString() const {
+        return fExternalTextureExtensionString;
+    }
+
     bool mustSwizzleInShader() const { return fMustSwizzleInShader; }
 
     /**
      * Returns a string which represents how to map from an internal GLFormat to a given
      * GrPixelConfig. The function mustSwizzleInShader determines whether this swizzle is applied
      * in the generated shader code or using sample state in the 3D API.
      */
     const char* getSwizzleMap(GrPixelConfig config) const { return fConfigSwizzle[config]; }
 
     GrGLSLGeneration generation() const { return fGLSLGeneration; }
@@ skipping 18 matching lines @@
 
     // Used for specific driver bug work arounds
     bool fCanUseMinAndAbsTogether : 1;
     bool fMustForceNegatedAtanParamToFloat : 1;
 
     const char* fVersionDeclString;
 
     const char* fShaderDerivativeExtensionString;
     const char* fFragCoordConventionsExtensionString;
     const char* fSecondaryOutputExtensionString;
+    const char* fExternalTextureExtensionString;
 
     const char* fFBFetchColorName;
     const char* fFBFetchExtensionString;
 
     AdvBlendEqInteraction fAdvBlendEqInteraction;
 
     bool        fMustSwizzleInShader;
     const char* fConfigSwizzle[kGrPixelConfigCnt];
 
     friend class GrGLCaps;  // For initialization.
 
     typedef GrShaderCaps INHERITED;
 };
 
 
 #endif