diff --git a/parser/html/nsHtml5Highlighter.cpp b/parser/html/nsHtml5Highlighter.cpp
index e232d18f84ee..042915a4a752 100644
--- a/parser/html/nsHtml5Highlighter.cpp
+++ b/parser/html/nsHtml5Highlighter.cpp
@@ -89,6 +89,11 @@ nsHtml5Highlighter::Start(const nsAutoString& aTitle)
// uses NS_NewHTMLSharedElement creator
Push(nsGkAtoms::head, nullptr, NS_NewHTMLSharedElement);
+ Push(nsGkAtoms::meta,
+ nsHtml5ViewSourceUtils::NewMetaViewportAttributes(),
+ NS_NewHTMLMetaElement);
+ Pop(); // meta
+
Push(nsGkAtoms::title, nullptr, NS_NewHTMLTitleElement);
// XUL will add the "Source of: " prefix.
uint32_t length = aTitle.Length();
diff --git a/parser/html/nsHtml5TreeBuilderCppSupplement.h b/parser/html/nsHtml5TreeBuilderCppSupplement.h
index 65255c2e5344..7dd4f4d2d221 100644
--- a/parser/html/nsHtml5TreeBuilderCppSupplement.h
+++ b/parser/html/nsHtml5TreeBuilderCppSupplement.h
@@ -1315,6 +1315,11 @@ void
nsHtml5TreeBuilder::StartPlainTextViewSource(const nsAutoString& aTitle)
{
MOZ_ASSERT(!mBuilder, "Must not view source with builder.");
+
+ startTag(nsHtml5ElementName::ELT_META,
+ nsHtml5ViewSourceUtils::NewMetaViewportAttributes(),
+ false);
+
startTag(nsHtml5ElementName::ELT_TITLE,
nsHtml5HtmlAttributes::EMPTY_ATTRIBUTES,
false);
diff --git a/parser/html/nsHtml5ViewSourceUtils.cpp b/parser/html/nsHtml5ViewSourceUtils.cpp
index 29879572631b..86fb8d8522d9 100644
--- a/parser/html/nsHtml5ViewSourceUtils.cpp
+++ b/parser/html/nsHtml5ViewSourceUtils.cpp
@@ -54,3 +54,15 @@ nsHtml5ViewSourceUtils::NewLinkAttributes()
linkAttrs->addAttribute(nsHtml5AttributeName::ATTR_HREF, href, -1);
return linkAttrs;
}
+
+// static
+nsHtml5HtmlAttributes*
+nsHtml5ViewSourceUtils::NewMetaViewportAttributes()
+{
+ nsHtml5HtmlAttributes* metaVpAttrs = new nsHtml5HtmlAttributes(0);
+ nsHtml5String name = nsHtml5Portability::newStringFromLiteral("viewport");
+ metaVpAttrs->addAttribute(nsHtml5AttributeName::ATTR_NAME, name, -1);
+ nsHtml5String content = nsHtml5Portability::newStringFromLiteral("width=device-width");
+ metaVpAttrs->addAttribute(nsHtml5AttributeName::ATTR_CONTENT, content, -1);
+ return metaVpAttrs;
+}
diff --git a/parser/html/nsHtml5ViewSourceUtils.h b/parser/html/nsHtml5ViewSourceUtils.h
index 1644801b69d2..058b65788e0c 100644
--- a/parser/html/nsHtml5ViewSourceUtils.h
+++ b/parser/html/nsHtml5ViewSourceUtils.h
@@ -12,6 +12,7 @@ class nsHtml5ViewSourceUtils
public:
static nsHtml5HtmlAttributes* NewBodyAttributes();
static nsHtml5HtmlAttributes* NewLinkAttributes();
+ static nsHtml5HtmlAttributes* NewMetaViewportAttributes();
};
#endif // nsHtml5ViewSourceUtils_h
diff --git a/toolkit/content/browser-content.js b/toolkit/content/browser-content.js
index 45db891a35ce..165a29a4b7cc 100644
--- a/toolkit/content/browser-content.js
+++ b/toolkit/content/browser-content.js
@@ -1402,7 +1402,8 @@ var ViewSelectionSource = {
var source =
""
+ ""
- + "" + title + ""
+ + ''
+ + "" + title + ""
+ ''
+ '