Implement GL support for buffer textures

src/gpu/GrTextureAccess.cpp

Index: src/gpu/GrTextureAccess.cpp
diff --git a/src/gpu/GrTextureAccess.cpp b/src/gpu/GrTextureAccess.cpp
index a62a4ddce013debe081a9c59473d834c6a2c52e4..931d9399567f401b30eb7bb88310fc631402cb0d 100644
--- a/src/gpu/GrTextureAccess.cpp
+++ b/src/gpu/GrTextureAccess.cpp
@@ -23,11 +23,18 @@ GrTextureAccess::GrTextureAccess(GrTexture* texture,
     this->reset(texture, filterMode, tileXAndY, visibility, precision);
 }
 
+GrTextureAccess::GrTextureAccess(GrTexture* texture,
+                                 GrShaderFlags visibility,
+                                 GrSLPrecision precision) {
+    this->reset(texture, visibility, precision);
+}
+
 void GrTextureAccess::reset(GrTexture* texture,
                             const GrTextureParams& params,
                             GrShaderFlags visibility,
                             GrSLPrecision precision) {
     SkASSERT(texture);
+    SkASSERT(texture->supportsTextureParams());
     fTexture.set(SkRef(texture), kRead_GrIOType);
     fParams = params;
     fVisibility = visibility;
@@ -40,8 +47,17 @@ void GrTextureAccess::reset(GrTexture* texture,
                             GrShaderFlags visibility,
                             GrSLPrecision precision) {
     SkASSERT(texture);
+    SkASSERT(texture->supportsTextureParams());
     fTexture.set(SkRef(texture), kRead_GrIOType);
     fParams.reset(tileXAndY, filterMode);
     fVisibility = visibility;
     fPrecision = precision;
 }
+
+void GrTextureAccess::reset(GrTexture* texture, GrShaderFlags visibility, GrSLPrecision precision) {
+    SkASSERT(texture);
+    SkASSERT(!texture->supportsTextureParams());
+    fTexture.set(SkRef(texture), kRead_GrIOType);
+    fVisibility = visibility;
+    fPrecision = precision;
+}