Use path outlines to define shadow shapes

Fixes the simplifying assumption that shadow casters were always
rectangular.

Java side APIs + plumbing to pass down correct shapes still need to be added.

Change-Id: Ic4fee90af15679951a44bb5cc6ae454b98c4c194
diff --git a/libs/hwui/OpenGLRenderer.h b/libs/hwui/OpenGLRenderer.h
index fb780ce..806e805 100644
--- a/libs/hwui/OpenGLRenderer.h
+++ b/libs/hwui/OpenGLRenderer.h
@@ -214,7 +214,7 @@
     virtual status_t drawRects(const float* rects, int count, const SkPaint* paint);
 
     status_t drawShadow(const mat4& casterTransform, float casterAlpha,
-            float width, float height);
+            const SkPath* casterOutline);
 
     virtual void resetShader();
     virtual void setupShader(SkiaShader* shader);