Add UseCounter for weird body+viewport scrolling
BUG=580570
Review URL: https://codereview.chromium.org/1619963002
Cr-Commit-Position: refs/heads/master@{#370990}
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 681c3f1..8635fbe 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -1637,6 +1637,12 @@
} else {
ASSERT(element == documentElement());
overflowStyle = documentElementStyle.get();
+
+ // The body element has its own scrolling box, independent from the viewport.
+ // This is a bit of a weird edge case in the CSS spec that we might want to try to
+ // eliminate some day (eg. for ScrollTopLeftInterop - see http://crbug.com/157855).
+ if (bodyStyle && !bodyStyle->isOverflowVisible())
+ UseCounter::count(*this, UseCounter::BodyScrollsInAdditionToViewport);
}
}
diff --git a/third_party/WebKit/Source/core/frame/UseCounter.h b/third_party/WebKit/Source/core/frame/UseCounter.h
index 8f72e4f..b000b003 100644
--- a/third_party/WebKit/Source/core/frame/UseCounter.h
+++ b/third_party/WebKit/Source/core/frame/UseCounter.h
@@ -982,6 +982,7 @@
MouseWheelEvent = 1125,
WheelEvent = 1126,
MouseWheelAndWheelEvent = 1127,
+ BodyScrollsInAdditionToViewport = 1128,
// Add new features immediately above this line. Don't change assigned
// numbers of any item, and don't reuse removed slots.
