Remove some checks that are never true in patterns code.

Change-Id: I8f589c1fa91d140e11d6ee4edd02daa30d224ac3
Reviewed-on: https://pdfium-review.googlesource.com/c/45190
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

core/fpdfapi/page/cpdf_docpagedata.cpp

diff --git a/core/fpdfapi/page/cpdf_docpagedata.cpp b/core/fpdfapi/page/cpdf_docpagedata.cpp
index 7b62467..eaadc96 100644
--- a/core/fpdfapi/page/cpdf_docpagedata.cpp
+++ b/core/fpdfapi/page/cpdf_docpagedata.cpp
@@ -342,8 +342,9 @@
 CPDF_Pattern* CPDF_DocPageData::GetPattern(CPDF_Object* pPatternObj,
                                            bool bShading,
                                            const CFX_Matrix& matrix) {
-  if (!pPatternObj)
-    return nullptr;
+  ASSERT(pPatternObj);
+  ASSERT(pPatternObj->IsDictionary() || pPatternObj->IsStream());
+  ASSERT(pPatternObj->GetDict());
 
   CPDF_CountedPattern* ptData = nullptr;
   auto it = m_PatternMap.find(pPatternObj);
@@ -359,9 +360,6 @@
         m_pPDFDoc.Get(), pPatternObj, true, matrix);
   } else {
     CPDF_Dictionary* pDict = pPatternObj->GetDict();
-    if (!pDict)
-      return nullptr;
-
     int type = pDict->GetIntegerFor("PatternType");
     if (type == CPDF_Pattern::TILING) {
       pPattern = pdfium::MakeUnique<CPDF_TilingPattern>(m_pPDFDoc.Get(),

core/fpdfapi/page/cpdf_tilingpattern.cpp

diff --git a/core/fpdfapi/page/cpdf_tilingpattern.cpp b/core/fpdfapi/page/cpdf_tilingpattern.cpp
index faa7eb8..ce01d8a 100644
--- a/core/fpdfapi/page/cpdf_tilingpattern.cpp
+++ b/core/fpdfapi/page/cpdf_tilingpattern.cpp
@@ -36,9 +36,6 @@
     return true;
 
   const CPDF_Dictionary* pDict = pattern_obj()->GetDict();
-  if (!pDict)
-    return false;
-
   m_bColored = pDict->GetIntegerFor("PaintType") == 1;
   m_XStep = static_cast<float>(fabs(pDict->GetNumberFor("XStep")));
   m_YStep = static_cast<float>(fabs(pDict->GetNumberFor("YStep")));