Refactor GrGLUniformManager::UniformHandle to initialize itself by default

src/gpu/gl/GrGLProgram.h

Index: src/gpu/gl/GrGLProgram.h
diff --git a/src/gpu/gl/GrGLProgram.h b/src/gpu/gl/GrGLProgram.h
index 3534552f9803756264531b2f56fc3faeeddbf0d1..279890f5d4a8858b7b103c95b77f04410a98bac5 100644
--- a/src/gpu/gl/GrGLProgram.h
+++ b/src/gpu/gl/GrGLProgram.h
@@ -132,17 +132,6 @@ private:
         UniformHandle       fDstCopyTopLeftUni;
         UniformHandle       fDstCopyScaleUni;
         UniformHandle       fDstCopySamplerUni;
-
-        UniformHandles() {
-            fViewMatrixUni = GrGLUniformManager::kInvalidUniformHandle;
-            fColorUni = GrGLUniformManager::kInvalidUniformHandle;
-            fCoverageUni = GrGLUniformManager::kInvalidUniformHandle;
-            fColorFilterUni = GrGLUniformManager::kInvalidUniformHandle;
-            fRTHeightUni = GrGLUniformManager::kInvalidUniformHandle;
-            fDstCopyTopLeftUni = GrGLUniformManager::kInvalidUniformHandle;
-            fDstCopyScaleUni = GrGLUniformManager::kInvalidUniformHandle;
-            fDstCopySamplerUni = GrGLUniformManager::kInvalidUniformHandle;
-        }
     };
 
     typedef SkSTArray<4, UniformHandle, true> SamplerUniSArray;