--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1739,17 +1739,17 @@ Element::UnbindFromTree(bool aDeep, bool
   }
   if (aNullParent) {
     if (IsFullScreenAncestor()) {
       // The element being removed is an ancestor of the full-screen element,
       // exit full-screen state.
       nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
                                       NS_LITERAL_CSTRING("DOM"), OwnerDoc(),
                                       nsContentUtils::eDOM_PROPERTIES,
-                                      "RemovedFullScreenElement");
+                                      "RemovedFullscreenElement");
       // Fully exit full-screen.
       nsIDocument::ExitFullscreenInDocTree(OwnerDoc());
     }
 
     if (GetParent() && GetParent()->IsInUncomposedDoc()) {
       // Update the editable descendant count in the ancestors before we
       // lose the reference to the parent.
       int32_t editableDescendantChange = -1 * EditableInclusiveDescendantCount(this);
@@ -3236,17 +3236,17 @@ GetFullScreenError(nsIDocument* aDoc)
     // Request is in a web app and in the same origin as the web app.
     // Don't enforce as strict security checks for web apps, the user
     // is supposed to have trust in them. However documents cross-origin
     // to the web app must still confirm to the normal security checks.
     return nullptr;
   }
 
   if (!nsContentUtils::IsRequestFullScreenAllowed()) {
-    return "FullScreenDeniedNotInputDriven";
+    return "FullscreenDeniedNotInputDriven";
   }
 
   return nullptr;
 }
 
 void
 Element::RequestFullscreen(JSContext* aCx, JS::Handle<JS::Value> aOptions,
                            ErrorResult& aError)

--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -11573,83 +11573,83 @@ GetFullscreenError(nsIDocument* aDoc, bo
     // Chrome code can always use the full-screen API, provided it's not
     // explicitly disabled. Note IsCallerChrome() returns true when running
     // in an nsRunnable, so don't use GetMozFullScreenEnabled() from an
     // nsRunnable!
     return nullptr;
   }
 
   if (!nsContentUtils::IsFullScreenApiEnabled()) {
-    return "FullScreenDeniedDisabled";
+    return "FullscreenDeniedDisabled";
   }
   if (!aDoc->IsVisible()) {
-    return "FullScreenDeniedHidden";
+    return "FullscreenDeniedHidden";
   }
   if (HasFullScreenSubDocument(aDoc)) {
-    return "FullScreenDeniedSubDocFullScreen";
+    return "FullscreenDeniedSubDocFullScreen";
   }
 
   // Ensure that all containing elements are <iframe> and have
   // allowfullscreen attribute set.
   nsCOMPtr<nsIDocShell> docShell(aDoc->GetDocShell());
   if (!docShell || !docShell->GetFullscreenAllowed()) {
-    return "FullScreenDeniedContainerNotAllowed";
+    return "FullscreenDeniedContainerNotAllowed";
   }
 
   return nullptr;
 }
 
 bool
 nsDocument::FullscreenElementReadyCheck(Element* aElement,
                                         bool aWasCallerChrome)
 {
   NS_ASSERTION(aElement,
     "Must pass non-null element to nsDocument::RequestFullScreen");
   if (!aElement || aElement == GetFullscreenElement()) {
     return false;
   }
   if (!aElement->IsInDoc()) {
-    DispatchFullscreenError("FullScreenDeniedNotInDocument");
+    DispatchFullscreenError("FullscreenDeniedNotInDocument");
     return false;
   }
   if (aElement->OwnerDoc() != this) {
-    DispatchFullscreenError("FullScreenDeniedMovedDocument");
+    DispatchFullscreenError("FullscreenDeniedMovedDocument");
     return false;
   }
   if (!GetWindow()) {
-    DispatchFullscreenError("FullScreenDeniedLostWindow");
+    DispatchFullscreenError("FullscreenDeniedLostWindow");
     return false;
   }
   if (const char* msg = GetFullscreenError(this, aWasCallerChrome)) {
     DispatchFullscreenError(msg);
     return false;
   }
   if (GetFullscreenElement() &&
       !nsContentUtils::ContentIsDescendantOf(aElement, GetFullscreenElement())) {
     // If this document is full-screen, only grant full-screen requests from
     // a descendant of the current full-screen element.
-    DispatchFullscreenError("FullScreenDeniedNotDescendant");
+    DispatchFullscreenError("FullscreenDeniedNotDescendant");
     return false;
   }
   if (!nsContentUtils::IsChromeDoc(this) && !IsInActiveTab(this)) {
-    DispatchFullscreenError("FullScreenDeniedNotFocusedTab");
+    DispatchFullscreenError("FullscreenDeniedNotFocusedTab");
     return false;
   }
   // Deny requests when a windowed plugin is focused.
   nsIFocusManager* fm = nsFocusManager::GetFocusManager();
   if (!fm) {
     NS_WARNING("Failed to retrieve focus manager in full-screen request.");
     return false;
   }
   nsCOMPtr<nsIDOMElement> focusedElement;
   fm->GetFocusedElement(getter_AddRefs(focusedElement));
   if (focusedElement) {
     nsCOMPtr<nsIContent> content = do_QueryInterface(focusedElement);
     if (nsContentUtils::HasPluginWithUncontrolledEventDispatch(content)) {
-      DispatchFullscreenError("FullScreenDeniedFocusedPlugin");
+      DispatchFullscreenError("FullscreenDeniedFocusedPlugin");
       return false;
     }
   }
   return true;
 }
 
 FullscreenRequest::FullscreenRequest(Element* aElement)
   : mElement(aElement)

--- a/dom/base/nsFocusManager.cpp
+++ b/dom/base/nsFocusManager.cpp
@@ -1231,17 +1231,17 @@ nsFocusManager::SetFocusInner(nsIContent
 #ifndef XP_MACOSX
   if (contentToFocus &&
       nsContentUtils::GetRootDocument(contentToFocus->OwnerDoc())->IsFullScreenDoc() &&
       nsContentUtils::HasPluginWithUncontrolledEventDispatch(contentToFocus)) {
     nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
                                     NS_LITERAL_CSTRING("DOM"),
                                     contentToFocus->OwnerDoc(),
                                     nsContentUtils::eDOM_PROPERTIES,
-                                    "FocusedWindowedPluginWhileFullScreen");
+                                    "FocusedWindowedPluginWhileFullscreen");
     nsIDocument::AsyncExitFullscreen(contentToFocus->OwnerDoc());
   }
 #endif
 
   // if the FLAG_NOSWITCHFRAME flag is used, only allow the focus to be
   // shifted away from the current element if the new shell to focus is
   // the same or an ancestor shell of the currently focused shell.
   bool allowFrameSwitch = !(aFlags & FLAG_NOSWITCHFRAME) ||

--- a/dom/locales/en-US/chrome/dom/dom.properties
+++ b/dom/locales/en-US/chrome/dom/dom.properties
@@ -59,29 +59,29 @@ CreateAttributeWarning=Use of document.c
 CreateAttributeNSWarning=Use of document.createAttributeNS() is deprecated. Use element.setAttributeNS() instead.
 OwnerElementWarning=Use of attributes' ownerElement attribute is deprecated.
 NodeValueWarning=Use of attributes' nodeValue attribute is deprecated. Use value instead.
 TextContentWarning=Use of attributes' textContent attribute is deprecated. Use value instead.
 EnablePrivilegeWarning=Use of enablePrivilege is deprecated.  Please use code that runs with the system principal (e.g. an extension) instead.
 nsIJSONDecodeDeprecatedWarning=nsIJSON.decode is deprecated.  Please use JSON.parse instead.
 nsIJSONEncodeDeprecatedWarning=nsIJSON.encode is deprecated.  Please use JSON.stringify instead.
 nsIDOMWindowInternalWarning=Use of nsIDOMWindowInternal is deprecated. Use nsIDOMWindow instead.
-FullScreenDeniedDisabled=Request for full-screen was denied because full-screen API is disabled by user preference.
-FullScreenDeniedFocusedPlugin=Request for full-screen was denied because a windowed plugin is focused.
-FullScreenDeniedHidden=Request for full-screen was denied because the document is no longer visible.
-FullScreenDeniedContainerNotAllowed=Request for full-screen was denied because at least one of the document's containing elements is not an iframe or does not have an "allowfullscreen" attribute.
-FullScreenDeniedNotInputDriven=Request for full-screen was denied because Element.mozRequestFullScreen() was not called from inside a short running user-generated event handler.
-FullScreenDeniedNotInDocument=Request for full-screen was denied because requesting element is no longer in its document.
-FullScreenDeniedMovedDocument=Request for full-screen was denied because requesting element has moved document.
-FullScreenDeniedLostWindow=Request for full-screen was denied because we no longer have a window.
-FullScreenDeniedSubDocFullScreen=Request for full-screen was denied because a subdocument of the document requesting full-screen is already full-screen.
-FullScreenDeniedNotDescendant=Request for full-screen was denied because requesting element is not a descendant of the current full-screen element.
-FullScreenDeniedNotFocusedTab=Request for full-screen was denied because requesting element is not in the currently focused tab.
-RemovedFullScreenElement=Exited full-screen because full-screen element was removed from document.
-FocusedWindowedPluginWhileFullScreen=Exited full-screen because windowed plugin was focused.
+FullscreenDeniedDisabled=Request for fullscreen was denied because Fullscreen API is disabled by user preference.
+FullscreenDeniedFocusedPlugin=Request for fullscreen was denied because a windowed plugin is focused.
+FullscreenDeniedHidden=Request for fullscreen was denied because the document is no longer visible.
+FullscreenDeniedContainerNotAllowed=Request for fullscreen was denied because at least one of the document's containing elements is not an iframe or does not have an "allowfullscreen" attribute.
+FullscreenDeniedNotInputDriven=Request for fullscreen was denied because Element.requestFullscreen() was not called from inside a short running user-generated event handler.
+FullscreenDeniedNotInDocument=Request for fullscreen was denied because requesting element is no longer in its document.
+FullscreenDeniedMovedDocument=Request for fullscreen was denied because requesting element has moved document.
+FullscreenDeniedLostWindow=Request for fullscreen was denied because we no longer have a window.
+FullscreenDeniedSubDocFullscreen=Request for fullscreen was denied because a subdocument of the document requesting fullscreen is already fullscreen.
+FullscreenDeniedNotDescendant=Request for fullscreen was denied because requesting element is not a descendant of the current fullscreen element.
+FullscreenDeniedNotFocusedTab=Request for fullscreen was denied because requesting element is not in the currently focused tab.
+RemovedFullscreenElement=Exited fullscreen because fullscreen element was removed from document.
+FocusedWindowedPluginWhileFullscreen=Exited fullscreen because windowed plugin was focused.
 HTMLSyncXHRWarning=HTML parsing in XMLHttpRequest is not supported in the synchronous mode.
 InvalidRedirectChannelWarning=Unable to redirect to %S because the channel doesn't implement nsIWritablePropertyBag2.
 ResponseTypeSyncXHRWarning=Use of XMLHttpRequest's responseType attribute is no longer supported in the synchronous mode in window context.
 WithCredentialsSyncXHRWarning=Use of XMLHttpRequest's withCredentials attribute is no longer supported in the synchronous mode in window context.
 TimeoutSyncXHRWarning=Use of XMLHttpRequest's timeout attribute is not supported in the synchronous mode in window context.
 JSONCharsetWarning=An attempt was made to declare a non-UTF-8 encoding for JSON retrieved using XMLHttpRequest. Only UTF-8 is supported for decoding JSON.
 # LOCALIZATION NOTE: Do not translate AudioBufferSourceNode
 MediaBufferSourceNodeResampleOutOfMemory=Insufficient memory to resample the AudioBufferSourceNode for playback.

--- a/webapprt/locales/en-US/webapprt/overrides/dom.properties
+++ b/webapprt/locales/en-US/webapprt/overrides/dom.properties
@@ -59,29 +59,29 @@ CreateAttributeWarning=Use of document.c
 CreateAttributeNSWarning=Use of document.createAttributeNS() is deprecated. Use element.setAttributeNS() instead.
 OwnerElementWarning=Use of attributes' ownerElement attribute is deprecated.
 NodeValueWarning=Use of attributes' nodeValue attribute is deprecated. Use value instead.
 TextContentWarning=Use of attributes' textContent attribute is deprecated. Use value instead.
 EnablePrivilegeWarning=Use of enablePrivilege is deprecated. Please use code that runs with the system principal (e.g. an extension) instead.
 nsIJSONDecodeDeprecatedWarning=nsIJSON.decode is deprecated. Please use JSON.parse instead.
 nsIJSONEncodeDeprecatedWarning=nsIJSON.encode is deprecated. Please use JSON.stringify instead.
 nsIDOMWindowInternalWarning=Use of nsIDOMWindowInternal is deprecated. Use nsIDOMWindow instead.
-FullScreenDeniedDisabled=Request for full-screen was denied because full-screen API is disabled by user preference.
-FullScreenDeniedFocusedPlugin=Request for full-screen was denied because a windowed plugin is focused.
-FullScreenDeniedHidden=Request for full-screen was denied because the document is no longer visible.
-FullScreenDeniedContainerNotAllowed=Request for full-screen was denied because at least one of the document's containing elements is not an iframe or does not have an "allowfullscreen" attribute.
-FullScreenDeniedNotInputDriven=Request for full-screen was denied because Element.mozRequestFullScreen() was not called from inside a short running user-generated event handler.
-FullScreenDeniedNotInDocument=Request for full-screen was denied because requesting element is no longer in its document.
-FullScreenDeniedMovedDocument=Request for full-screen was denied because requesting element has moved document.
-FullScreenDeniedLostWindow=Request for full-screen was denied because we no longer have a window.
-FullScreenDeniedSubDocFullScreen=Request for full-screen was denied because a subdocument of the document requesting full-screen is already full-screen.
-FullScreenDeniedNotDescendant=Request for full-screen was denied because requesting element is not a descendant of the current full-screen element.
-FullScreenDeniedNotFocusedTab=Request for full-screen was denied because requesting element is not in the currently focused tab.
-RemovedFullScreenElement=Exited full-screen because full-screen element was removed from document.
-FocusedWindowedPluginWhileFullScreen=Exited full-screen because windowed plugin was focused.
+FullscreenDeniedDisabled=Request for fullscreen was denied because Fullscreen API is disabled by user preference.
+FullscreenDeniedFocusedPlugin=Request for fullscreen was denied because a windowed plugin is focused.
+FullscreenDeniedHidden=Request for fullscreen was denied because the document is no longer visible.
+FullscreenDeniedContainerNotAllowed=Request for fullscreen was denied because at least one of the document's containing elements is not an iframe or does not have an "allowfullscreen" attribute.
+FullscreenDeniedNotInputDriven=Request for fullscreen was denied because Element.requestFullscreen() was not called from inside a short running user-generated event handler.
+FullscreenDeniedNotInDocument=Request for fullscreen was denied because requesting element is no longer in its document.
+FullscreenDeniedMovedDocument=Request for fullscreen was denied because requesting element has moved document.
+FullscreenDeniedLostWindow=Request for fullscreen was denied because we no longer have a window.
+FullscreenDeniedSubDocFullscreen=Request for fullscreen was denied because a subdocument of the document requesting fullscreen is already fullscreen.
+FullscreenDeniedNotDescendant=Request for fullscreen was denied because requesting element is not a descendant of the current fullscreen element.
+FullscreenDeniedNotFocusedTab=Request for fullscreen was denied because requesting element is not in the currently focused tab.
+RemovedFullscreenElement=Exited fullscreen because fullscreen element was removed from document.
+FocusedWindowedPluginWhileFullscreen=Exited fullscreen because windowed plugin was focused.
 HTMLSyncXHRWarning=HTML parsing in XMLHttpRequest is not supported in the synchronous mode.
 InvalidRedirectChannelWarning=Unable to redirect to %S because the channel doesn't implement nsIWritablePropertyBag2.
 ResponseTypeSyncXHRWarning=Use of XMLHttpRequest's responseType attribute is no longer supported in the synchronous mode in window context.
 WithCredentialsSyncXHRWarning=Use of XMLHttpRequest's withCredentials attribute is no longer supported in the synchronous mode in window context.
 TimeoutSyncXHRWarning=Use of XMLHttpRequest's timeout attribute is not supported in the synchronous mode in window context.
 JSONCharsetWarning=An attempt was made to declare a non-UTF-8 encoding for JSON retrieved using XMLHttpRequest. Only UTF-8 is supported for decoding JSON.
 # LOCALIZATION NOTE: Do not translate AudioBufferSourceNode
 MediaBufferSourceNodeResampleOutOfMemory=Insufficient memory to resample the AudioBufferSourceNode for playback.