cc: Rename PictureLayerTiling(Set) Iterator to CoverageIterator

cc/resources/picture_layer_tiling_unittest.cc

Index: cc/resources/picture_layer_tiling_unittest.cc
diff --git a/cc/resources/picture_layer_tiling_unittest.cc b/cc/resources/picture_layer_tiling_unittest.cc
index 4f3c656ed875206233527433dcb51f48e62f8506..91043e67b48006e13d72f42781c97fd55828fcdb 100644
--- a/cc/resources/picture_layer_tiling_unittest.cc
+++ b/cc/resources/picture_layer_tiling_unittest.cc
@@ -40,9 +40,8 @@ class PictureLayerTilingIteratorTest : public testing::Test {
     ASSERT_LE(dest_to_contents_scale, 2.0);
 
     Region remaining = expect_rect;
-    for (PictureLayerTiling::Iterator iter(tiling_.get(),
-                                           rect_scale,
-                                           request_rect);
+    for (PictureLayerTiling::CoverageIterator
+             iter(tiling_.get(), rect_scale, request_rect);
          iter;
          ++iter) {
       // Geometry cannot overlap previous geometry at all
@@ -142,14 +141,14 @@ TEST_F(PictureLayerTilingIteratorTest, IteratorEmptyRect) {
   Initialize(gfx::Size(100, 100), 1.0f, gfx::Size(800, 600));
 
   gfx::Rect empty;
-  PictureLayerTiling::Iterator iter(tiling_.get(), 1.0f, empty);
+  PictureLayerTiling::CoverageIterator iter(tiling_.get(), 1.0f, empty);
   EXPECT_FALSE(iter);
 }
 
 TEST_F(PictureLayerTilingIteratorTest, NonIntersectingRect) {
   Initialize(gfx::Size(100, 100), 1.0f, gfx::Size(800, 600));
   gfx::Rect non_intersecting(1000, 1000, 50, 50);
-  PictureLayerTiling::Iterator iter(tiling_.get(), 1, non_intersecting);
+  PictureLayerTiling::CoverageIterator iter(tiling_.get(), 1, non_intersecting);
   EXPECT_FALSE(iter);
 }