Do not give GPU memory to backgrounded compositors.

cc/trees/layer_tree_host_unittest_damage.cc

Index: cc/trees/layer_tree_host_unittest_damage.cc
diff --git a/cc/trees/layer_tree_host_unittest_damage.cc b/cc/trees/layer_tree_host_unittest_damage.cc
index 402a56a8986f0185bc96a1b64c3b577ae661067e..4c28738a9c3d9d9d2062a74a05ff9c2f038e0dee 100644
--- a/cc/trees/layer_tree_host_unittest_damage.cc
+++ b/cc/trees/layer_tree_host_unittest_damage.cc
@@ -54,15 +54,6 @@ class LayerTreeHostDamageTestSetVisibleDoesNotDraw
       case 0:
         // The first frame has full damage.
         EXPECT_EQ(gfx::RectF(10.f, 10.f).ToString(), root_damage.ToString());
-
-        // No evictions when we become not-visible.
-        impl->SetMemoryPolicy(ManagedMemoryPolicy(
-            1000 * 1000 * 1000,
-            gpu::MemoryAllocation::CUTOFF_ALLOW_EVERYTHING,
-            1000 * 1000 * 1000,
-            gpu::MemoryAllocation::CUTOFF_ALLOW_EVERYTHING,
-            ManagedMemoryPolicy::kDefaultNumResourcesLimit));
-
         PostSetVisibleToMainThread(false);
         break;
       case 1:
@@ -74,12 +65,24 @@ class LayerTreeHostDamageTestSetVisibleDoesNotDraw
       case 2:
         // The compositor has been set visible again.
         EXPECT_TRUE(impl->visible());
-        // But it still does not draw.
-        NOTREACHED();
+        if (!impl->settings().impl_side_painting) {
+          // Evicting resources for non-impl-side painting will trigger a full
+          // redraw.
+          EXPECT_EQ(gfx::RectF(10.f, 10.f).ToString(), root_damage.ToString());
+        } else {
+          // Otherwise there will be no redraw.
+          NOTREACHED();
+        }
         break;
       case 3:
-        // Finally we force a draw, but it will have no damage.
-        EXPECT_EQ(gfx::RectF().ToString(), root_damage.ToString());
+        if (impl->settings().impl_side_painting && !delegating_renderer()) {
+          // The forced draw will have full damage with a direct impl-side
+          // painting renderer.
+          EXPECT_EQ(gfx::RectF(10.f, 10.f).ToString(), root_damage.ToString());
+        } else {
+          // Finally we force a draw, but it will have no damage.
+          EXPECT_EQ(gfx::RectF().ToString(), root_damage.ToString());
+        }
         EndTest();
         break;
       case 4: