Alter layer hoisting to only hoist layers for one canvas at a time

tests/GpuLayerCacheTest.cpp

Index: tests/GpuLayerCacheTest.cpp
diff --git a/tests/GpuLayerCacheTest.cpp b/tests/GpuLayerCacheTest.cpp
index 62f6ec7a8c207888e4c74feb67bb028c89ef78c1..0a8d0d2442468a39a181ab7844351f90e6e97c35 100644
--- a/tests/GpuLayerCacheTest.cpp
+++ b/tests/GpuLayerCacheTest.cpp
@@ -66,10 +66,14 @@ static void lock_layer(skiatest::Reporter* reporter,
     desc.fHeight = 512;
     desc.fConfig = kSkia8888_GrPixelConfig;
 
-    bool needsRerendering = cache->lock(layer, desc, false);
+    bool needsRerendering;
+    bool inAtlas = cache->tryToAtlas(layer, desc, &needsRerendering);
+    if (!inAtlas) {
+        cache->lock(layer, desc, &needsRerendering);
+    }
     REPORTER_ASSERT(reporter, needsRerendering);
 
-    needsRerendering = cache->lock(layer, desc, false);
+    cache->lock(layer, desc, &needsRerendering);
     REPORTER_ASSERT(reporter, !needsRerendering);
 
     REPORTER_ASSERT(reporter, layer->texture());