Fix GLSL error on Android.

src/gpu/effects/GrMatrixConvolutionEffect.cpp

Index: src/gpu/effects/GrMatrixConvolutionEffect.cpp
diff --git a/src/gpu/effects/GrMatrixConvolutionEffect.cpp b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
index f6b99eff8f77705af5721caf57fb9dfa31d18506..0b0a8af1944bc49d8c1824f2b23f1ddf7378ae48 100644
--- a/src/gpu/effects/GrMatrixConvolutionEffect.cpp
+++ b/src/gpu/effects/GrMatrixConvolutionEffect.cpp
@@ -90,7 +90,7 @@ void GrGLMatrixConvolutionEffect::emitCode(GrGLFPBuilder* builder,
             fDomain.sampleTexture(fsBuilder, domain, "c", coord, samplers[0]);
             if (!fConvolveAlpha) {
                 fsBuilder->codeAppend("c.rgb /= c.a;");
-                fsBuilder->codeAppend("c.rgb = clamp(c.rgb, 0, 1);");
+                fsBuilder->codeAppend("c.rgb = clamp(c.rgb, 0.0, 1.0);");
             }
             fsBuilder->codeAppend("sum += c * k;");
         }