Fix unsafety in SkiaShader storage, and texture unit accounting

bug:22390304

Fixes two issues:

1) The max texture unit wasn't large enough to handle the most complex
ComposeShader case (1 for draw primitive, 2 for gradient shader, 1 for
bitmap shader).

2) If a shader isn't supported by SkiaShader::store, the shader data
needs to be explicitly disabled, so we won't read uninitilized data
from it when trying to read shader information out.

Change-Id: I29ee7b7c1e07f67db88c1707bdc857daa305e713

1 files changed, 4 insertions, 0 deletions

diff --git a/libs/hwui/SkiaShader.cpp b/libs/hwui/SkiaShader.cpp
index 2cfb9e1..a2aa2d1 100644
--- a/libs/hwui/SkiaShader.cpp
+++ b/libs/hwui/SkiaShader.cpp
@@ -370,7 +370,11 @@ void SkiaShader::store(Caches& caches, const SkShader& shader, const Matrix4& mo
     if (tryStoreLayer(caches, shader, modelViewMatrix,
             textureUnit, description, &outData->layerData)) {
         outData->skiaShaderType = kLayer_SkiaShaderType;
+        return;
     }
+
+    // Unknown/unsupported type, so explicitly ignore shader
+    outData->skiaShaderType = kNone_SkiaShaderType;
 }
 
 void SkiaShader::apply(Caches& caches, const SkiaShaderData& data) {