Bug 799407: Fix warnings under layout/generic, r=roc

layout/generic/nsObjectFrame.cpp

@@ -1269,8 +1269,8 @@ nsObjectFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
 
       nsTArray<nsNPAPIPluginInstance::VideoInfo*> videos;
       mInstanceOwner->GetVideos(videos);
-      
-      for (int i = 0; i < videos.Length(); i++) {
+
+      for (uint32_t i = 0; i < videos.Length(); i++) {
         rv = replacedContent.AppendNewToTop(new (aBuilder)
           nsDisplayPluginVideo(aBuilder, this, videos[i]));
         NS_ENSURE_SUCCESS(rv, rv);

layout/generic/nsTextFrameThebes.cpp

@@ -4680,7 +4680,7 @@ nsTextFrame::GetTextDecorations(
   const nsCompatibility compatMode = aPresContext->CompatibilityMode();
 
   bool useOverride = false;
-  nscolor overrideColor;
+  nscolor overrideColor = NS_RGBA(0, 0, 0, 0);
 
   // frameTopOffset represents the offset to f's top from our baseline in our
   // coordinate space