Add support for linear gradients.

Change-Id: Id15329da065045b3f06fdaed615f33cd57608496
diff --git a/libs/hwui/TextureCache.cpp b/libs/hwui/TextureCache.cpp
index ff7d7c9..ff9e2aff 100644
--- a/libs/hwui/TextureCache.cpp
+++ b/libs/hwui/TextureCache.cpp
@@ -97,6 +97,7 @@
     } else if (bitmap->getGenerationID() != texture->generation) {
         generateTexture(bitmap, texture, true);
     }
+    // TODO: Do something to destroy the texture object if it's too big for the cache
     return texture;
 }