Bug 1393536 Clean up unused variables in widget/ r=jimm

MozReview-Commit-ID: 9NBzIriF8NU

widget/nsBaseWidget.cpp

@@ -2285,7 +2285,7 @@ nsIWidget::CaptureRegisteredPlugins(uintptr_t aOwnerWidget)
   // a specific top level window. We use the parent widget during iteration
   // to skip the plugin widgets owned by other top level windows.
   for (auto iter = sPluginWidgetList->Iter(); !iter.Done(); iter.Next()) {
-    const void* windowId = iter.Key();
+    DebugOnly<const void*> windowId = iter.Key();
     nsIWidget* widget = iter.UserData();
 
     MOZ_ASSERT(windowId);

widget/windows/GfxInfo.cpp

@@ -598,8 +598,8 @@ GfxInfo::Init()
 
     if (createDXGIFactory) {
       RefPtr<IDXGIFactory> factory = nullptr;
-      HRESULT hrf = createDXGIFactory(__uuidof(IDXGIFactory),
-                                      (void**)(&factory) );
+      createDXGIFactory(__uuidof(IDXGIFactory),
+                        (void**)(&factory) );
       if (factory) {
         RefPtr<IDXGIAdapter> adapter;
         if (SUCCEEDED(factory->EnumAdapters(0, getter_AddRefs(adapter)))) {

widget/windows/nsWindow.cpp

@@ -3774,7 +3774,6 @@ nsWindow::EnableDragDrop(bool aEnable)
 {
   NS_ASSERTION(mWnd, "nsWindow::EnableDragDrop() called after Destroy()");
 
-  nsresult rv = NS_ERROR_FAILURE;
   if (aEnable) {
     if (!mNativeDragTarget) {
       mNativeDragTarget = new nsNativeDragTarget(this);
@@ -7306,9 +7305,7 @@ nsWindow::OnDPIChanged(int32_t x, int32_t y, int32_t width, int32_t height)
   if (DefaultScaleOverride() > 0.0) {
     return;
   }
-  double oldScale = mDefaultScale;
   mDefaultScale = -1.0; // force recomputation of scale factor
-  double newScale = GetDefaultScaleInternal();
 
   if (mResizeState != RESIZING && mSizeMode == nsSizeMode_Normal) {
     // Limit the position (if not in the middle of a drag-move) & size,
@@ -7708,7 +7705,7 @@ VOID CALLBACK nsWindow::HookTimerForPopups(HWND hwnd, UINT uMsg, UINT idEvent, D
 {
   if (sHookTimerId != 0) {
     // if the window is nullptr then we need to use the ID to kill the timer
-    BOOL status = ::KillTimer(nullptr, sHookTimerId);
+    DebugOnly<BOOL> status = ::KillTimer(nullptr, sHookTimerId);
     NS_ASSERTION(status, "Hook Timer was not killed.");
     sHookTimerId = 0;
   }