Add support for SweepGradient in the GL renderer.

Change-Id: I7aa397ed4e34655ead9ba1f5b4ce087665e0f022
diff --git a/libs/hwui/GradientCache.h b/libs/hwui/GradientCache.h
index 51a8c01..c829fd4 100644
--- a/libs/hwui/GradientCache.h
+++ b/libs/hwui/GradientCache.h
@@ -46,8 +46,8 @@
      * Adds a new linear gradient to the cache. The generated texture is
      * returned.
      */
-    Texture* addLinearGradient(SkShader* shader, float* bounds, uint32_t* colors,
-            float* positions, int count, SkShader::TileMode tileMode);
+    Texture* addLinearGradient(SkShader* shader, uint32_t* colors, float* positions,
+            int count, SkShader::TileMode tileMode = SkShader::kClamp_TileMode);
     /**
      * Returns the texture associated with the specified shader.
      */