Ensure the viewport is always represented by the inner viewport layer.

cc/trees/layer_tree_host_impl_unittest.cc

Index: cc/trees/layer_tree_host_impl_unittest.cc
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index f388371f89f7ff192d284dec3eaed633ee35ca59..69637013e7957654530a0b8b5540cf4ed62e6b54 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -3668,7 +3668,7 @@ TEST_F(LayerTreeHostImplTopControlsTest, TopControlsScrollOuterViewport) {
   EXPECT_EQ(InputHandler::SCROLL_STARTED,
             host_impl_->ScrollBegin(gfx::Point(), InputHandler::GESTURE));
   host_impl_->ScrollBy(gfx::Point(), scroll_delta);
-  EXPECT_EQ(host_impl_->OuterViewportScrollLayer(),
+  EXPECT_EQ(host_impl_->InnerViewportScrollLayer(),
             host_impl_->CurrentlyScrollingLayer());
   host_impl_->ScrollEnd();
 
@@ -3682,7 +3682,7 @@ TEST_F(LayerTreeHostImplTopControlsTest, TopControlsScrollOuterViewport) {
   host_impl_->ScrollBy(gfx::Point(), scroll_delta);
 
   EXPECT_EQ(0, host_impl_->top_controls_manager()->ContentTopOffset());
-  EXPECT_EQ(host_impl_->OuterViewportScrollLayer(),
+  EXPECT_EQ(host_impl_->InnerViewportScrollLayer(),
             host_impl_->CurrentlyScrollingLayer());
 
   host_impl_->ScrollEnd();
@@ -7750,15 +7750,15 @@ TEST_F(LayerTreeHostImplVirtualViewportTest, FlingScrollBubblesToInner) {
     // currently scrolling layer.
     EXPECT_EQ(InputHandler::SCROLL_STARTED,
               host_impl_->ScrollBegin(gfx::Point(), InputHandler::GESTURE));
-    EXPECT_EQ(outer_scroll, host_impl_->CurrentlyScrollingLayer());
+    EXPECT_EQ(inner_scroll, host_impl_->CurrentlyScrollingLayer());
     EXPECT_EQ(InputHandler::SCROLL_STARTED, host_impl_->FlingScrollBegin());
-    EXPECT_EQ(outer_scroll, host_impl_->CurrentlyScrollingLayer());
+    EXPECT_EQ(inner_scroll, host_impl_->CurrentlyScrollingLayer());
 
     gfx::Vector2d scroll_delta(inner_viewport.width() / 2.f,
                                inner_viewport.height() / 2.f);
     host_impl_->ScrollBy(gfx::Point(), scroll_delta);
     inner_expected += gfx::Vector2dF(scroll_delta.x(), scroll_delta.y());
-    EXPECT_EQ(host_impl_->CurrentlyScrollingLayer(), outer_scroll);
+    EXPECT_EQ(inner_scroll, host_impl_->CurrentlyScrollingLayer());
 
     host_impl_->ScrollEnd();
     EXPECT_EQ(nullptr, host_impl_->CurrentlyScrollingLayer());
@@ -7769,17 +7769,17 @@ TEST_F(LayerTreeHostImplVirtualViewportTest, FlingScrollBubblesToInner) {
     // Fling past the inner viewport boundry, make sure outer viewport scrolls.
     EXPECT_EQ(InputHandler::SCROLL_STARTED,
               host_impl_->ScrollBegin(gfx::Point(), InputHandler::GESTURE));
-    EXPECT_EQ(outer_scroll, host_impl_->CurrentlyScrollingLayer());
+    EXPECT_EQ(inner_scroll, host_impl_->CurrentlyScrollingLayer());
     EXPECT_EQ(InputHandler::SCROLL_STARTED, host_impl_->FlingScrollBegin());
-    EXPECT_EQ(outer_scroll, host_impl_->CurrentlyScrollingLayer());
+    EXPECT_EQ(inner_scroll, host_impl_->CurrentlyScrollingLayer());
 
     host_impl_->ScrollBy(gfx::Point(), scroll_delta);
     inner_expected += gfx::Vector2dF(scroll_delta.x(), scroll_delta.y());
-    EXPECT_EQ(outer_scroll, host_impl_->CurrentlyScrollingLayer());
+    EXPECT_EQ(inner_scroll, host_impl_->CurrentlyScrollingLayer());
 
     host_impl_->ScrollBy(gfx::Point(), scroll_delta);
     outer_expected += gfx::Vector2dF(scroll_delta.x(), scroll_delta.y());
-    EXPECT_EQ(outer_scroll, host_impl_->CurrentlyScrollingLayer());
+    EXPECT_EQ(inner_scroll, host_impl_->CurrentlyScrollingLayer());
 
     host_impl_->ScrollEnd();
     EXPECT_EQ(nullptr, host_impl_->CurrentlyScrollingLayer());