cc: Consider scroll offset in CalcDrawProperties

cc/trees/layer_tree_host_unittest_scroll.cc

Index: cc/trees/layer_tree_host_unittest_scroll.cc
diff --git a/cc/trees/layer_tree_host_unittest_scroll.cc b/cc/trees/layer_tree_host_unittest_scroll.cc
index 47393f99f2904ac0c2909e62d43d1dab4ec64bb1..0bd7ffa6ca6c49712fe7940182178b23c9baf1b6 100644
--- a/cc/trees/layer_tree_host_unittest_scroll.cc
+++ b/cc/trees/layer_tree_host_unittest_scroll.cc
@@ -140,8 +140,9 @@ class LayerTreeHostScrollTestScrollMultipleRedraw
       EXPECT_VECTOR_EQ(root->scroll_offset(), initial_scroll_);
       PostSetNeedsCommitToMainThread();
     } else if (impl->active_tree()->source_frame_number() == 1) {
-      // Third or later draw after second commit.
-      EXPECT_GE(impl->SourceAnimationFrameNumber(), 3);
+      // Any draw after second commit.  The animation frame may not update
+      // if no damage occurs here and the draw is skipped.
+      EXPECT_GE(impl->SourceAnimationFrameNumber(), 2);

[danakj, 2013/07/08 21:53:42]

Does this mean we do the above elseif{} block (sourceframe=0,
sourceanimationframe=2) and then also this block (sourceframe=1,
sourceanimationframe=2)? Ie, new source frame, but the source animation frame
number didn't change?

Or is the block above being skipped and some of this test isn't testing
anything?

[enne (OOO), 2013/07/08 22:03:46]

All three blocks run in order on different "draws".  The third time the draw may
not occur because there's no damage, as the comment implies.  I could force some
damage if you think that'd make it clearer.
Nope.  The above block is also running.

[enne (OOO), 2013/07/09 00:49:45]

I fixed this case by resizing the root.  Now that scroll offsets move layers
(via the large initial scroll offset in this test), this layer got scrolled
offscreen and so its damage no longer affected the viewport.

       EXPECT_VECTOR_EQ(root->ScrollDelta(), gfx::Vector2d());
       EXPECT_VECTOR_EQ(root->scroll_offset(),
                        initial_scroll_ + scroll_amount_ + scroll_amount_);
@@ -238,7 +239,7 @@ class LayerTreeHostScrollTestCaseWithChild : public LayerTreeHostScrollTest {
     root_scroll_layer_ = ContentLayer::Create(&fake_content_layer_client_);
     root_scroll_layer_->SetBounds(gfx::Size(110, 110));
 
-    root_scroll_layer_->SetPosition(gfx::Point(0, 0));
+    root_scroll_layer_->SetPosition(gfx::Point());
     root_scroll_layer_->SetAnchorPoint(gfx::PointF());
 
     root_scroll_layer_->SetIsDrawable(true);
@@ -252,10 +253,17 @@ class LayerTreeHostScrollTestCaseWithChild : public LayerTreeHostScrollTest {
                    base::Unretained(this)));
     child_layer_->SetBounds(gfx::Size(110, 110));
 
-    // Scrolls on the child layer will happen at 5, 5. If they are treated
-    // like device pixels, and device scale factor is 2, then they will
-    // be considered at 2.5, 2.5 in logical pixels, and will miss this layer.
-    child_layer_->SetPosition(gfx::Point(5, 5));
+    if (scroll_child_layer_) {
+      child_layer_->SetPosition(gfx::Point());
+    } else {
+      // Offset the child layer further than the sum of all scrolls so that
+      // scrolls beginning at the viewport origin will always hit the root.
+      child_layer_->SetPosition(gfx::Point(60, 60));
+      EXPECT_GT(child_layer_->position().x(),
+                (initial_offset_ + javascript_scroll_).x());
+      EXPECT_GT(child_layer_->position().y(),
+                (initial_offset_ + javascript_scroll_).y());
+    }
     child_layer_->SetAnchorPoint(gfx::PointF());
 
     child_layer_->SetIsDrawable(true);
@@ -345,10 +353,8 @@ class LayerTreeHostScrollTestCaseWithChild : public LayerTreeHostScrollTest {
     switch (impl->active_tree()->source_frame_number()) {
       case 0: {
         // Gesture scroll on impl thread.
-        InputHandler::ScrollStatus status = impl->ScrollBegin(
-            gfx::ToCeiledPoint(expected_scroll_layer_impl->position() +
-                               gfx::Vector2dF(0.5f, 0.5f)),
-            InputHandler::Gesture);
+        InputHandler::ScrollStatus status =
+            impl->ScrollBegin(gfx::Point(), InputHandler::Gesture);
         EXPECT_EQ(InputHandler::ScrollStarted, status);
         impl->ScrollBy(gfx::Point(), scroll_amount_);
         impl->ScrollEnd();
@@ -362,10 +368,8 @@ class LayerTreeHostScrollTestCaseWithChild : public LayerTreeHostScrollTest {
       }
       case 1: {
         // Wheel scroll on impl thread.
-        InputHandler::ScrollStatus status = impl->ScrollBegin(
-            gfx::ToCeiledPoint(expected_scroll_layer_impl->position() +
-                               gfx::Vector2dF(0.5f, 0.5f)),
-            InputHandler::Wheel);
+        InputHandler::ScrollStatus status =
+            impl->ScrollBegin(gfx::Point(), InputHandler::Wheel);
         EXPECT_EQ(InputHandler::ScrollStarted, status);
         impl->ScrollBy(gfx::Point(), scroll_amount_);
         impl->ScrollEnd();