import changes from `dev' branch of rmottola/Arctic-Fox:

- reapply Bug 1574573 - Disambiguate a use of Handle in XPCShellEnvironment.cpp r=Ehsan (a674c4b006)
- Bug 1255707 - Part 2. Remove ScreenSizeChanged. r=snorp (3a93e4e768)
- Bug 1250418 - Remove the assertion check of mCanSend in CompositorCh ld::ActorDestroy, r=nical (14bb402a1d)
- Bug 1250718 - Improve layer logging for preserve-3d layers. r=thinker (f373a50040)
- Bug 1232042 - Addendum: Add comment for mLayerManager check. r=jrmuizel (2b69aa784a)
- Bug 1239861. Skip composite if vsync time is before force composite time. r=kats (5ee4038157)
- Bug 1241678 - Fix low-volume null-deref crash. r=BenWa (b28d944615)
- Rename PCompositor to PCompositorBridge. (bug 1258479 part 2, r=mattwoodrow) (dd535a9bdd)
- Bug 1220184 - Eliminate Gingerbread compatibility. r=froydnj, r=nalexander (dce9e4f9e8)
- Bug 1250917 - Remove NS_SUCCESS_I_DID_SOMETHING; r=bholley (9dd6fe351b)
- Bug 1155241: Check mInstanceOwner for nullptr in nsObjectLoadingContent::PluginDestroyed; r=smaug (ad60991e3e)
- Bug 1229220 - Update the scrollbar visibility prefs when initializing a TabChild; r=smaug (28997e0a6d)
- Bug 1252262 - Don't combine the client offset into the outer rect for the child process. r=jimm (f415c0418e)
- Bug 1249943 - Make test_basic_pan work on Fennec and Linux as well. r=botond (657c940be1)
- bit of bug 1245765 part 5 (82463f7eaa)
- Bug 1207512 - Remove the JS_IsRunning call in nsObjectLoadingContent::ScriptRequestPluginInstance; r=bholley (76047284a6)
- Bug 1239463 - Do not assert when notifying an inactive document about changed content from the plugin crash notification. r=bz (03bf38a683)
- Bug 1192450 - Remove PlayPreview registration from Shumway. r=jet (9b6e131876)
- Bug 1200602 - Use the alternate content for <applet>. r=kmachulis (843fccf0aa)

docshell/base/nsWebNavigationInfo.cpp

@@ -51,6 +51,13 @@ nsWebNavigationInfo::IsTypeSupported(const nsACString& aType,
     return NS_OK;
   }
 
+  // We want to claim that the type for SWF movies is unsupported,
+  // so that the internal SWF player's stream converter will get used.
+  if (aType.LowerCaseEqualsLiteral("application/x-shockwave-flash") &&
+      nsContentUtils::IsSWFPlayerEnabled()) {
+    return NS_OK;
+  }
+
   const nsCString& flatType = PromiseFlatCString(aType);
   nsresult rv = IsTypeSupportedInternal(flatType, aIsTypeSupported);
   NS_ENSURE_SUCCESS(rv, rv);