Cache VectorDrawables in an atlas

Optimize VectorDrawables for Skia pipeline: draw small VectorDrawables
in a GPU atlas instead of seprate offscreen buffers.
This implementation is using CacheManger and allows for the atlas to
be released if there is a memory pressure.

Test: A new unit test for VectorDrawableAtlas is passing. Systrace shows
0.5ms faster DrawFrame for fling in Settings app main screen.
Change-Id: Ide3884eefae777e1547f1dfdb67b807185839fb4
diff --git a/libs/hwui/renderthread/CacheManager.h b/libs/hwui/renderthread/CacheManager.h
index 43d58f2..90362f3 100644
--- a/libs/hwui/renderthread/CacheManager.h
+++ b/libs/hwui/renderthread/CacheManager.h
@@ -22,6 +22,7 @@
 #include <ui/DisplayInfo.h>
 #include <utils/String8.h>
 #include <vector>
+#include "pipeline/skia/VectorDrawableAtlas.h"
 
 namespace android {
 
@@ -36,11 +37,6 @@
 class IRenderPipeline;
 class RenderThread;
 
-struct VectorDrawableAtlas {
-    sk_sp<SkSurface> surface;
-    bool isNewAtlas = true;
-};
-
 class CacheManager {
 public:
     enum class TrimMemoryMode {
@@ -53,8 +49,7 @@
     void trimStaleResources();
     void dumpMemoryUsage(String8& log, const RenderState* renderState = nullptr);
 
-    VectorDrawableAtlas* acquireVectorDrawableAtlas();
-    void releaseVectorDrawableAtlas(VectorDrawableAtlas*);
+    sp<skiapipeline::VectorDrawableAtlas> acquireVectorDrawableAtlas();
 
     size_t getCacheSize() const { return mMaxResourceBytes; }
     size_t getBackgroundCacheSize() const { return mBackgroundResourceBytes; }
@@ -81,7 +76,7 @@
         size_t surfaceArea = 0;
     };
 
-    std::unique_ptr<VectorDrawableAtlas> mVectorDrawableAtlas;
+    sp<skiapipeline::VectorDrawableAtlas> mVectorDrawableAtlas;
 };
 
 } /* namespace renderthread */