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

- Bug 1163201 - Part 1: Remove instances of #ifdef PR_LOGGING in dom/. r=froydnj (9979c0e74)
-  Bug 1183972 - No sync-dispatch of new GMPParent - r=cpearce (93339b530)
- Bug 1142935 - reset transports with NuwaAddConstructor(). r=tlee (277406812)
- Bug 1121676 - Use a lock to protect the list of top-level actors (r=bent) (3d0be2f87)
-  Bug 1121676 - Use static mutex to protect top-level protocols (r=bent) (4491dd318)
- Bug 1163201 - Part 2: Wrap expensive calls in PR_LOG_TEST. r=froydnj (7de4b9a97)
- Bug 1163201 - Part 3: Remove mSamples in |MediaEngineWebRTCAudioSource|. r=cpeterson (452442773)
- Bug 1163201 - Part 4: Fix b2g build. r=bustage (a824ea36d)
- Bug 1165518 - Part 1: Add Logging.h. r=froydnj (09d68aaa6)
- Bug 1162850 - Don't stop looking for style sheet load finishes after the FontFaceSet gets a DOMContentLoaded. r=jdaggett (c29fbffa0)
- Bug 1056479 p0 - rename ambiguous GetFontList method in Android fontlist. r=m_kato (76239d7a0)
- Bug 1056479 p1 - add language to FindFamily parameters. r=jfkthame (2271bd7d0)
- Bug 1056479 p1a - use lang as part of pref font fallback. r=karlt (5f5fd66c5)
- cleanup GetTableFromFontData() to match gecko code again (78076fc26)
- Bug 1056479 p2 - implement platform fontlist based on fontconfig. r=karlt (6a7631e44)
- Bug 1056479 p3 - fixup various reftests for Linux. r=jfkthame (b25360708)
- Bug 1056479 p4 - fix accessibility api for font-weight. r=jfkthame (efa8f5080)
- Bug 1056479 p5 - fixup printpreview test. r=jfkthame (3fe2ddc0b)
- Bug 1056479 p6 - handle font updates. r=jfkthame (eb78b2c54)
- Bug 1056479 p7 - fixup assertion for non-italic fallback. r=m_kato (f5e9f539e)
- Bug 1056479 p8 - switch gfxFontConfig to gfxFontconfig. r=karlt (4da146b50)
- Bug 1056479 p9 - fix build bustage. r=birtles (28f246c2b)
- Bug 1056479 p10 - activate bundled fonts. r=m_kato (d7627c3fa)
- Bug 1056479 p10 - activate bundled fonts. r=m_kato (251c02315)
- Bug 1056479 followup: Annotate gfxPlatformGtk::CreatePlatformFontList() as 'override'. rs=ehsan (993e65d6e)

dom/html/HTMLTrackElement.cpp

@@ -39,12 +39,8 @@
 #include "nsThreadUtils.h"
 #include "nsVideoFrame.h"
 
-#ifdef PR_LOGGING
 static PRLogModuleInfo* gTrackElementLog;
 #define LOG(type, msg) PR_LOG(gTrackElementLog, type, msg)
-#else
-#define LOG(type, msg)
-#endif
 
 // Replace the usual NS_IMPL_NS_NEW_HTML_ELEMENT(Track) so
 // we can return an UnknownElement instead when pref'd off.
@@ -79,11 +75,9 @@ static MOZ_CONSTEXPR const char* kKindTableDefaultString = kKindTable->tag;
 HTMLTrackElement::HTMLTrackElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
   : nsGenericHTMLElement(aNodeInfo)
 {
-#ifdef PR_LOGGING
   if (!gTrackElementLog) {
     gTrackElementLog = PR_NewLogModule("nsTrackElement");
   }
-#endif
 }
 
 HTMLTrackElement::~HTMLTrackElement()