Unpin images when skia pipeline object is destroyed

Unpin images when skia pipeline object is destroyed. This fixes
an assert in skia ~SkImage_Raster.

Test: Built and ran Android on a device.
Bug: 66730647
Change-Id: I73603efd4fc2ca584cdb8f6a4774e48a187f6787
diff --git a/libs/hwui/pipeline/skia/SkiaPipeline.cpp b/libs/hwui/pipeline/skia/SkiaPipeline.cpp
index 6f117de..c4bd1e1 100644
--- a/libs/hwui/pipeline/skia/SkiaPipeline.cpp
+++ b/libs/hwui/pipeline/skia/SkiaPipeline.cpp
@@ -45,6 +45,10 @@
     mVectorDrawables.reserve(30);
 }
 
+SkiaPipeline::~SkiaPipeline() {
+    unpinImages();
+}
+
 TaskManager* SkiaPipeline::getTaskManager() {
     return mRenderThread.cacheManager().getTaskManager();
 }
diff --git a/libs/hwui/pipeline/skia/SkiaPipeline.h b/libs/hwui/pipeline/skia/SkiaPipeline.h
index 2b0c419..3e6ae30 100644
--- a/libs/hwui/pipeline/skia/SkiaPipeline.h
+++ b/libs/hwui/pipeline/skia/SkiaPipeline.h
@@ -28,7 +28,7 @@
 class SkiaPipeline : public renderthread::IRenderPipeline {
 public:
     SkiaPipeline(renderthread::RenderThread& thread);
-    virtual ~SkiaPipeline() {}
+    virtual ~SkiaPipeline();
 
     TaskManager* getTaskManager() override;