Refactor GrGLUniformManager::UniformHandle to initialize itself by default

src/gpu/gl/GrGLShaderBuilder.cpp

Index: src/gpu/gl/GrGLShaderBuilder.cpp
diff --git a/src/gpu/gl/GrGLShaderBuilder.cpp b/src/gpu/gl/GrGLShaderBuilder.cpp
index 36eb6d5169ebd23a3eb7104f801ab8bb102ac9c9..5ed8f0da09c5bd90fed30f10a117f45a55d3048b 100644
--- a/src/gpu/gl/GrGLShaderBuilder.cpp
+++ b/src/gpu/gl/GrGLShaderBuilder.cpp
@@ -110,9 +110,6 @@ GrGLShaderBuilder::GrGLShaderBuilder(const GrGLContextInfo& ctxInfo,
     , fUsesGS(false)
 #endif
     , fSetupFragPosition(false)
-    , fRTHeightUniform(GrGLUniformManager::kInvalidUniformHandle)
-    , fDstCopyTopLeftUniform (GrGLUniformManager::kInvalidUniformHandle)
-    , fDstCopyScaleUniform (GrGLUniformManager::kInvalidUniformHandle)
     , fTopLeftFragPosRead(kTopLeftFragPosRead_FragPosKey == desc.getHeader().fFragPosKey) {
 
     const GrGLProgramDesc::KeyHeader& header = desc.getHeader();
@@ -391,7 +388,7 @@ GrGLUniformManager::UniformHandle GrGLShaderBuilder::addUniformArray(uint32_t vi
     GrAssert(0 != visibility);
 
     BuilderUniform& uni = fUniforms.push_back();
-    UniformHandle h = index_to_handle(fUniforms.count() - 1);
+    UniformHandle h = GrGLUniformManager::UniformHandle::CreateFromUniformIndex(fUniforms.count() - 1);
     GR_DEBUGCODE(UniformHandle h2 =)
     fUniformManager.appendUniform(type, count);
     // We expect the uniform manager to initially have no uniforms and that all uniforms are added
@@ -418,10 +415,6 @@ GrGLUniformManager::UniformHandle GrGLShaderBuilder::addUniformArray(uint32_t vi
     return h;
 }
 
-const GrGLShaderVar& GrGLShaderBuilder::getUniformVariable(UniformHandle u) const {
-    return fUniforms[handle_to_index(u)].fVariable;
-}
-
 bool GrGLShaderBuilder::addAttribute(GrSLType type,
                                      const char* name) {
     for (int i = 0; i < fVSAttrs.count(); ++i) {
@@ -512,7 +505,7 @@ const char* GrGLShaderBuilder::fragmentPosition() {
             // temporarily change the stage index because we're inserting non-stage code.
             CodeStage::AutoStageRestore csar(&fCodeStage, NULL);
 
-            GrAssert(GrGLUniformManager::kInvalidUniformHandle == fRTHeightUniform);
+            GrAssert(!fRTHeightUniform.isValid());
             const char* rtHeightName;
 
             fRTHeightUniform = this->addUniform(kFragment_ShaderType,
@@ -524,7 +517,7 @@ const char* GrGLShaderBuilder::fragmentPosition() {
                                    kCoordName, rtHeightName);
             fSetupFragPosition = true;
         }
-        GrAssert(GrGLUniformManager::kInvalidUniformHandle != fRTHeightUniform);
+        GrAssert(fRTHeightUniform.isValid());
         return kCoordName;
     }
 }