Bug 1194954 - Fix -Wunreachable-code warnings in gfx/layers and gfx/thebes. r=BenWa

gfx/layers/LayerTreeInvalidation.cpp

@@ -483,11 +483,15 @@ CloneLayerTreePropertiesInternal(Layer* aRoot, bool aIsMask /* = false */)
       return MakeUnique<ColorLayerProperties>(static_cast<ColorLayer*>(aRoot));
     case Layer::TYPE_IMAGE:
       return MakeUnique<ImageLayerProperties>(static_cast<ImageLayer*>(aRoot), aIsMask);
-    default:
+    case Layer::TYPE_CANVAS:
+    case Layer::TYPE_READBACK:
+    case Layer::TYPE_SHADOW:
+    case Layer::TYPE_PAINTED:
       return MakeUnique<LayerPropertiesBase>(aRoot);
   }
 
-  return UniquePtr<LayerPropertiesBase>(nullptr);
+  MOZ_ASSERT_UNREACHABLE("Unexpected root layer type");
+  return MakeUnique<LayerPropertiesBase>(aRoot);
 }
 
 /* static */ UniquePtr<LayerProperties>

gfx/thebes/gfxPlatform.cpp

@@ -2065,26 +2065,19 @@ gfxPlatform::GetLog(eGfxLog aWhichLog)
     switch (aWhichLog) {
     case eGfxLog_fontlist:
         return sFontlistLog;
-        break;
     case eGfxLog_fontinit:
         return sFontInitLog;
-        break;
     case eGfxLog_textrun:
         return sTextrunLog;
-        break;
     case eGfxLog_textrunui:
         return sTextrunuiLog;
-        break;
     case eGfxLog_cmapdata:
         return sCmapDataLog;
-        break;
     case eGfxLog_textperf:
         return sTextPerfLog;
-        break;
-    default:
-        break;
     }
 
+    MOZ_ASSERT_UNREACHABLE("Unexpected log type");
     return nullptr;
 }