Invalidate LayoutView when the URL bar is hidden on short pages.

third_party/WebKit/Source/core/layout/LayoutView.cpp

Index: third_party/WebKit/Source/core/layout/LayoutView.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutView.cpp b/third_party/WebKit/Source/core/layout/LayoutView.cpp
index 5beaba0026a59918b137bad08e3d1bce8224b2a5..fad2609f14eee7929194500c3f334ce685bc15d5 100644
--- a/third_party/WebKit/Source/core/layout/LayoutView.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutView.cpp
@@ -229,9 +229,9 @@ void LayoutView::layout() {
   IncludeScrollbarsInRect includeScrollbars =
       RuntimeEnabledFeatures::rootLayerScrollingEnabled() ? IncludeScrollbars
                                                           : ExcludeScrollbars;
-  FloatSize viewSize(frameView()->visibleContentSize(includeScrollbars));
   setShouldDoFullPaintInvalidationOnResizeIfNeeded(
-      offsetWidth() != viewSize.width(), offsetHeight() != viewSize.height());
+      offsetWidth() != layoutSize(includeScrollbars).width(),

[bokan, 2016/12/22 00:45:49]

In https://codereview.chromium.org/2461463004, I moved these
`widthChanged`|`heightChanged` calculations from
setShouldDoFullPaintInvalidationOnResizeIfNeeded to the call sites and passed
them as parameters. I made a mistake though in that I assumed
viewWidth|viewHeight == visibleContentSize -- they are not. viewWidth|viewHeight
are actually layoutWidth and layoutHeight. The mistake wasn't caught because it
was masked by the invalidation that happens in FrameView::viewportSizeChanged.
Now that I've tightened that up to happen only when there's a mobile URL bar it
caused window-resize-background-image-generated|fixed.html to fail.

+      offsetHeight() != layoutSize(includeScrollbars).height());
 
   if (pageLogicalHeight() && shouldUsePrintingLayout()) {
     m_minPreferredLogicalWidth = m_maxPreferredLogicalWidth = logicalWidth();