Bug 1676301. Only set mResolutionUpdated if we are changing the resolution. r=kats

We incorrectly set it when going from the mResolution.isNothing() to the *mResolution == 1.f case. Differential Revision: https://phabricator.services.mozilla.com/D97385
2020-11-19 01:01:02 +00:00 · 2020-11-19 01:01:02 +00:00 · c9931b44d2
--- a/layout/base/PresShell.cpp
+++ b/layout/base/PresShell.cpp
@ -5385,6 +5385,11 @@ nsresult PresShell::SetResolutionAndScaleTo(float aResolution,
    MOZ_ASSERT(mResolution.isSome());
    return NS_OK;
  }
+
+  // GetResolution handles mResolution being nothing by returning 1 so this
+  // is checking that the resolution is actually changing.
+  bool resolutionUpdated = (aResolution != GetResolution());
+
  RenderingState state(this);
  state.mResolution = Some(aResolution);
  SetRenderingState(state);
@ -5393,7 +5398,7 @@ nsresult PresShell::SetResolutionAndScaleTo(float aResolution,
  }
  if (aOrigin == ResolutionChangeOrigin::Apz) {
    mResolutionUpdatedByApz = true;
-  } else {
+  } else if (resolutionUpdated) {
    mResolutionUpdated = true;
  }

--- a/layout/base/crashtests/1676301-1.html
+++ b/layout/base/crashtests/1676301-1.html
@ -0,0 +1,16 @@
+<style>
+#a { max-width: 1 }
+</style>
+<script>
+function go() {
+  a.value = ">"
+  a.selectionDirection = "foo"
+  b.requestFullscreen()
+  document.createElement("body").onresize = () => { a.selectionEnd = 0 }
+  setTimeout(window.close, 100)
+}
+</script>
+<body onload=go()>
+<textarea id="a"></textarea>
+<ol id="b">
+<div>
--- a/layout/base/crashtests/crashtests.list
+++ b/layout/base/crashtests/crashtests.list
@ -554,3 +554,4 @@ load 1586600.html
 load 1599518.html
 load 1599532.html
 pref(layout.accessiblecaret.enabled,true) load 1606492.html
+load 1676301-1.html