cc: Fix memory limit edge cases for SetIsLikelyToRequireADraw.

cc/resources/tile_manager_unittest.cc

Index: cc/resources/tile_manager_unittest.cc
diff --git a/cc/resources/tile_manager_unittest.cc b/cc/resources/tile_manager_unittest.cc
index e826f55d7713754729b99e0ffc8f45ddc0337520..567e182cbb21067a860bcd8c9699d213104b3742 100644
--- a/cc/resources/tile_manager_unittest.cc
+++ b/cc/resources/tile_manager_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "cc/resources/eviction_tile_priority_queue.h"
 #include "cc/resources/raster_tile_priority_queue.h"
+#include "cc/resources/resource_pool.h"
 #include "cc/resources/tile.h"
 #include "cc/resources/tile_priority.h"
 #include "cc/resources/tiling_set_raster_queue_all.h"
@@ -1299,7 +1300,7 @@ TEST_F(TileManagerTilePriorityQueueTest, SetIsLikelyToRequireADraw) {
 }
 
 TEST_F(TileManagerTilePriorityQueueTest,
-       NoSetIsLikelyToRequireADrawOnZeroMemoryBudget) {
+       SetIsLikelyToRequireADrawOnZeroMemoryBudget) {
   const gfx::Size layer_bounds(1000, 1000);
   host_impl_.SetViewportSize(layer_bounds);
   SetupDefaultTrees(layer_bounds);
@@ -1319,5 +1320,62 @@ TEST_F(TileManagerTilePriorityQueueTest,
   EXPECT_FALSE(host_impl_.is_likely_to_require_a_draw());
 }
 
+TEST_F(TileManagerTilePriorityQueueTest,
+       SetIsLikelyToRequireADrawOnLimitedMemoryBudget) {
+  const gfx::Size layer_bounds(1000, 1000);
+  host_impl_.SetViewportSize(layer_bounds);
+  SetupDefaultTrees(layer_bounds);
+
+  // Verify that the queue has a required for draw tile at Top.
+  scoped_ptr<RasterTilePriorityQueue> queue(host_impl_.BuildRasterQueue(
+      SAME_PRIORITY_FOR_BOTH_TREES, RasterTilePriorityQueue::Type::ALL));
+  EXPECT_FALSE(queue->IsEmpty());
+  EXPECT_TRUE(queue->Top()->required_for_draw());
+  EXPECT_EQ(queue->Top()->desired_texture_size(), gfx::Size(256, 256));
+  EXPECT_EQ(host_impl_.tile_manager()
+                ->TileTaskRunnerForTesting()

[vmpstr, 2015/03/27 17:23:28]

This is kind of an overkill to get the tile task runner from tile manager just
to check the resource format... Is there another way to get this or is this the
best place?

[sunnyps, 2015/03/27 18:38:04]

Done. Using ResourceProvider::best_texture_format for this. The intent here is
to communicate what the numbers mean if the test ever breaks.

+                ->GetResourceFormat(),
+            RGBA_8888);
+
+  ManagedMemoryPolicy policy = host_impl_.ActualManagedMemoryPolicy();
+  policy.bytes_limit_when_visible = 256 * 256 * 4;
+  host_impl_.SetMemoryPolicy(policy);
+
+  EXPECT_FALSE(host_impl_.is_likely_to_require_a_draw());
+  host_impl_.tile_manager()->PrepareTiles(host_impl_.global_tile_state());
+  EXPECT_TRUE(host_impl_.is_likely_to_require_a_draw());
+
+  scoped_ptr<ScopedResource> resource =
+      host_impl_.resource_pool()->AcquireResource(gfx::Size(256, 256),
+                                                  RGBA_8888);
+
+  host_impl_.tile_manager()->CheckIfMoreTilesNeedToBePreparedForTesting();
+  EXPECT_FALSE(host_impl_.is_likely_to_require_a_draw());
+
+  host_impl_.resource_pool()->ReleaseResource(resource.Pass());
+}
+
+TEST_F(TileManagerTilePriorityQueueTest,
+       SetIsLikelyToRequireADrawOnSynchronousRaster) {
+  const gfx::Size layer_bounds(1000, 1000);
+  host_impl_.SetViewportSize(layer_bounds);
+  host_impl_.SetUseGpuRasterization(true);
+  EXPECT_EQ(host_impl_.rasterizer()->GetPrepareTilesMode(),
+            PrepareTilesMode::PREPARE_NONE);
+  SetupDefaultTrees(layer_bounds);
+
+  // Verify that the queue has a required for draw tile at Top.
+  scoped_ptr<RasterTilePriorityQueue> queue(host_impl_.BuildRasterQueue(
+      SAME_PRIORITY_FOR_BOTH_TREES, RasterTilePriorityQueue::Type::ALL));
+  EXPECT_FALSE(queue->IsEmpty());
+  EXPECT_TRUE(queue->Top()->required_for_draw());
+
+  host_impl_.SetIsLikelyToRequireADraw(true);
+
+  EXPECT_TRUE(host_impl_.is_likely_to_require_a_draw());
+  host_impl_.tile_manager()->UpdateVisibleTiles(host_impl_.global_tile_state());
+  EXPECT_FALSE(host_impl_.is_likely_to_require_a_draw());
+}
+
 }  // namespace
 }  // namespace cc