made point lights linear attenuation; also fixed point light depth bug

src/core/SkRadialShadowMapShader.cpp

Index: src/core/SkRadialShadowMapShader.cpp
diff --git a/src/core/SkRadialShadowMapShader.cpp b/src/core/SkRadialShadowMapShader.cpp
index 24b54a5e2be3a1f2271c194b7e2dddbf076e1ff7..f34616dcccf16ce899d896fcbd6c705908d9fb2b 100644
--- a/src/core/SkRadialShadowMapShader.cpp
+++ b/src/core/SkRadialShadowMapShader.cpp
@@ -142,7 +142,7 @@ public:
 
             // Modify the input texture coordinates to index into our 1D output
             fragBuilder->codeAppend("float distHere;");
-            fragBuilder->codeAppend("float closestDistHere = 0;");
+            fragBuilder->codeAppend("float closestDistHere = 2;");

[jvanverth1, 2016/09/09 18:18:33]

Why 2?

[vjiaoblack, 2016/09/09 18:24:36]

Done.

             fragBuilder->codeAppend("vec2 coords = vMatrixCoord_0_0_Stage0;");
             fragBuilder->codeAppend("coords.y = 0;");
             fragBuilder->codeAppend("vec2 destCoords = vec2(0,0);");