Track texture memory globally

Also mostly consolidates texture creation

Change-Id: Ifea01303afda531dcec99b8fe2a0f64cf2f24420
diff --git a/libs/hwui/GradientCache.h b/libs/hwui/GradientCache.h
index 7534c5d..b762ca7 100644
--- a/libs/hwui/GradientCache.h
+++ b/libs/hwui/GradientCache.h
@@ -143,7 +143,8 @@
     Texture* addLinearGradient(GradientCacheEntry& gradient,
             uint32_t* colors, float* positions, int count);
 
-    void generateTexture(uint32_t* colors, float* positions, Texture* texture);
+    void generateTexture(uint32_t* colors, float* positions,
+            const uint32_t width, const uint32_t height, Texture* texture);
 
     struct GradientInfo {
         uint32_t width;