fix null check bugs found by µmix static analyzer

src/ports/SkFontMgr_win_dw.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTypes.h"
 #if defined(SK_BUILD_FOR_WIN32)
 
@@ skipping 27 matching lines @@
 
     // IDWriteFontFileLoader methods
     virtual HRESULT STDMETHODCALLTYPE CreateStreamFromKey(
         void const* fontFileReferenceKey,
         UINT32 fontFileReferenceKeySize,
         IDWriteFontFileStream** fontFileStream);
 
     // Takes ownership of stream.
     static HRESULT Create(SkStreamAsset* stream, StreamFontFileLoader** streamFontFileLoader) {
         *streamFontFileLoader = new StreamFontFileLoader(stream);
-        if (nullptr == streamFontFileLoader) {
+        if (nullptr == *streamFontFileLoader) {
             return E_OUTOFMEMORY;
         }
         return S_OK;
     }
 
     SkAutoTDelete<SkStreamAsset> fStream;
 
 private:
     StreamFontFileLoader(SkStreamAsset* stream) : fStream(stream), fRefCount(1) { }
     virtual ~StreamFontFileLoader() { }
@@ skipping 43 matching lines @@
     virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID iid, void** ppvObject);
     virtual ULONG STDMETHODCALLTYPE AddRef();
     virtual ULONG STDMETHODCALLTYPE Release();
 
     // IDWriteFontFileEnumerator methods
     virtual HRESULT STDMETHODCALLTYPE MoveNext(BOOL* hasCurrentFile);
     virtual HRESULT STDMETHODCALLTYPE GetCurrentFontFile(IDWriteFontFile** fontFile);
 
     static HRESULT Create(IDWriteFactory* factory, IDWriteFontFileLoader* fontFileLoader,
                           StreamFontFileEnumerator** streamFontFileEnumerator) {
         *streamFontFileEnumerator = new StreamFontFileEnumerator(factory, fontFileLoader);

[reed1, 2016/06/08 10:35:10]

This seems like a crazy test in the first place -- we NEVER assume that 'new'
will return nullptr. Ben?

-        if (nullptr == streamFontFileEnumerator) {
+        if (nullptr == *streamFontFileEnumerator) {
             return E_OUTOFMEMORY;
         }
         return S_OK;
     }
 private:
     StreamFontFileEnumerator(IDWriteFactory* factory, IDWriteFontFileLoader* fontFileLoader);
     virtual ~StreamFontFileEnumerator() { }
 
     ULONG fRefCount;
 
@@ skipping 76 matching lines @@
     // IDWriteFontCollectionLoader methods
     virtual HRESULT STDMETHODCALLTYPE CreateEnumeratorFromKey(
         IDWriteFactory* factory,
         void const* collectionKey,
         UINT32 collectionKeySize,
         IDWriteFontFileEnumerator** fontFileEnumerator);
 
     static HRESULT Create(IDWriteFontFileLoader* fontFileLoader,
                           StreamFontCollectionLoader** streamFontCollectionLoader) {
         *streamFontCollectionLoader = new StreamFontCollectionLoader(fontFileLoader);
-        if (nullptr == streamFontCollectionLoader) {
+        if (nullptr == *streamFontCollectionLoader) {
             return E_OUTOFMEMORY;
         }
         return S_OK;
     }
 private:
     StreamFontCollectionLoader(IDWriteFontFileLoader* fontFileLoader)
         : fRefCount(1)
         , fFontFileLoader(SkRefComPtr(fontFileLoader))
     { }
     virtual ~StreamFontCollectionLoader() { }
@@ skipping 865 matching lines @@
 
 #include "SkFontMgr_indirect.h"
 SK_API SkFontMgr* SkFontMgr_New_DirectWriteRenderer(SkRemotableFontMgr* proxy) {
     SkAutoTUnref<SkFontMgr> impl(SkFontMgr_New_DirectWrite());
     if (impl.get() == nullptr) {
         return nullptr;
     }
     return new SkFontMgr_Indirect(impl.get(), proxy);
 }
 #endif//defined(SK_BUILD_FOR_WIN32)