Makes tile-creation lazy

cc/resources/picture_layer_tiling_unittest.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/resources/picture_layer_tiling.h"
 
 #include "cc/test/fake_picture_layer_tiling_client.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/rect_conversions.h"
 #include "ui/gfx/size_conversions.h"
 
 namespace cc {
 namespace {
 
+class TestablePictureLayerTiling : public PictureLayerTiling {
+ public:
+  using PictureLayerTiling::SetLiveTilesRect;
+
+  static scoped_ptr<TestablePictureLayerTiling> Create(
+      float contents_scale,
+      gfx::Size layer_bounds,
+      PictureLayerTilingClient* client) {
+    return make_scoped_ptr(new TestablePictureLayerTiling(
+        contents_scale,
+        layer_bounds,
+        client));
+  }
+
+ protected:
+  TestablePictureLayerTiling(float contents_scale,
+                             gfx::Size layer_bounds,
+                             PictureLayerTilingClient* client)
+      : PictureLayerTiling(contents_scale, layer_bounds, client) { }
+};
+
 class PictureLayerTilingIteratorTest : public testing::Test {
  public:
   PictureLayerTilingIteratorTest() {}
   virtual ~PictureLayerTilingIteratorTest() {}
 
   void Initialize(gfx::Size tile_size,
                   float contents_scale,
                   gfx::Size layer_bounds) {
     client_.SetTileSize(tile_size);
-    tiling_ = PictureLayerTiling::Create(contents_scale);
-    tiling_->SetClient(&client_);
-    tiling_->SetLayerBounds(layer_bounds);
+    tiling_ = TestablePictureLayerTiling::Create(contents_scale,
+                                                 layer_bounds,
+                                                 &client_);
+    tiling_->CreateAllTilesForTesting();
+  }
+
+  void SetLiveRectAndVerifyTiles(gfx::Rect live_tiles_rect) {
+    tiling_->SetLiveTilesRect(live_tiles_rect);  // max tiles in tile manager

[enne (OOO), 2013/04/11 00:16:02]

I don't think this comment is true, and could just be removed.

+
+    std::vector<Tile*> tiles = tiling_->AllTilesForTesting();
+    for (std::vector<Tile*>::iterator iter = tiles.begin();
+          iter != tiles.end();

[enne (OOO), 2013/04/11 00:16:02]

style nit: don't indent 5 spaces after a for loop

+          ++iter) {
+      EXPECT_EQ(*iter != NULL,

[enne (OOO), 2013/04/11 00:16:02]

Now that the loop has changed, this is a little bit weird.  I think you should
only be checking the second condition.  Every tile in the map should be true. 
If you're worried about NULL tiles, then AllTilesForTesting would be a better
place to check for that.

+                live_tiles_rect.Intersects((*iter)->content_rect()));
+    }
   }
 
   void VerifyTilesExactlyCoverRect(
       float rect_scale,
       gfx::Rect request_rect,
       gfx::Rect expect_rect) {
     EXPECT_TRUE(request_rect.Contains(expect_rect));
 
     // Iterators are not valid if this ratio is too large (i.e. the
     // tiling is too high-res for a low-res destination rect.)  This is an
@@ skipping 48 matching lines @@
   void VerifyTilesCoverNonContainedRect(float rect_scale, gfx::Rect dest_rect) {
     float dest_to_contents_scale = tiling_->contents_scale() / rect_scale;
     gfx::Rect clamped_rect(gfx::ToEnclosingRect(gfx::ScaleRect(
         tiling_->ContentRect(), 1 / dest_to_contents_scale)));
     clamped_rect.Intersect(dest_rect);
     VerifyTilesExactlyCoverRect(rect_scale, dest_rect, clamped_rect);
   }
 
  protected:
   FakePictureLayerTilingClient client_;
-  scoped_ptr<PictureLayerTiling> tiling_;
+  scoped_ptr<TestablePictureLayerTiling> tiling_;
 
   DISALLOW_COPY_AND_ASSIGN(PictureLayerTilingIteratorTest);
 };
 
+TEST_F(PictureLayerTilingIteratorTest, LiveTilesExactlyCoverLiveTileRect) {
+  Initialize(gfx::Size(100, 100), 1, gfx::Size(1099, 801));
+  SetLiveRectAndVerifyTiles(gfx::Rect(100, 100));
+  SetLiveRectAndVerifyTiles(gfx::Rect(101, 99));
+  SetLiveRectAndVerifyTiles(gfx::Rect(1099, 1));
+  SetLiveRectAndVerifyTiles(gfx::Rect(1, 801));
+  SetLiveRectAndVerifyTiles(gfx::Rect(1099, 1));
+  SetLiveRectAndVerifyTiles(gfx::Rect(201, 800));
+}
+
 TEST_F(PictureLayerTilingIteratorTest, IteratorCoversLayerBoundsNoScale) {
   Initialize(gfx::Size(100, 100), 1, gfx::Size(1099, 801));
   VerifyTilesExactlyCoverRect(1, gfx::Rect());
   VerifyTilesExactlyCoverRect(1, gfx::Rect(0, 0, 1099, 801));
   VerifyTilesExactlyCoverRect(1, gfx::Rect(52, 83, 789, 412));
 
   // With borders, a size of 3x3 = 1 pixel of content.
   Initialize(gfx::Size(3, 3), 1, gfx::Size(10, 10));
   VerifyTilesExactlyCoverRect(1, gfx::Rect(0, 0, 1, 1));
   VerifyTilesExactlyCoverRect(1, gfx::Rect(0, 0, 2, 2));
@@ skipping 331 matching lines @@
       layer_bounds,  // last layer bounds
       layer_bounds,  // current layer bounds
       1.f,  // last contents scale
       1.f,  // current contents scale
       gfx::Transform(),  // last screen transform
       gfx::Transform(),  // current screen transform
       2,  // current frame number
       2.0,  // current frame time
       false,  // store screen space quads on tiles
       10000);  // max tiles in tile manager
-  VerifyTiles(1.f, gfx::Rect(layer_bounds), base::Bind(&TileExists, false));
+  VerifyTiles(1.f, gfx::Rect(), base::Bind(&TileExists, false));
 }
 
 }  // namespace
 }  // namespace cc