In order to facilitate the movement of code with side-effects called by Element::SetAttr to Element::BeforeSetAttr and Element::AfterSetAttr, Element::AfterSetAttr should have access to the old value of the attribute. This includes information about whether there was previously a value set or not.
Accomplishing this involved passing an additional argument through functions that find and change the old attribute value in order to ensure that we can differentiate between an empty old value and an absent old value (attribute was not set).
Note that while I tried to ensure that accurate values (and their absence) are reported to Element::AfterSetAttr, I largely ignored SVG. While the old value reported for SVG values should be however accurate the value already being reported to SetAttrAndNotify was, SVG elements do not currently report unset values properly because they will never pass a null pointer to SetAttrAndNotify.
MozReview-Commit-ID: K1mha8CNFZP
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extra : rebase_source : 42776eb01451d371e4aebcc17fe3dd112c8d268b
clang's -Wcomma warning warns about suspicious use of the comma operator such as between two statements.
dom/svg/SVGGeometryElement.h:117:21 [-Wcomma] possible misuse of comma operator here
dom/svg/SVGGeometryElement.h:117:41 [-Wcomma] possible misuse of comma operator here
dom/svg/SVGGeometryElement.h:128:14 [-Wcomma] possible misuse of comma operator here
dom/svg/SVGGeometryElement.h:128:23 [-Wcomma] possible misuse of comma operator here
MozReview-Commit-ID: CfNOsfcJTEp
--HG--
extra : rebase_source : a9cda16923d853b4b9fd26d796ba1a6739e85383
extra : source : 91d3b4d038285c034294ea3164c4e55e300e4823
Kirk Steuber
Chris Peterson
Robert Longson
Sebastian Hengst