core: fix -Wshadow warnings

Found with this patch:

	diff --git a/BUILD.gn b/BUILD.gn
	index 83bad1b13..444685f04 100644
	--- a/BUILD.gn
	+++ b/BUILD.gn
	@@ -89,6 +89,8 @@ config("pdfium_core_config") {
	       "/wd4324",
	       "/wd4577",
	     ]
	+  } else {
	+      cflags += [ "-Wshadow" ]
	   }
	 }

But renaming the conflicting names is tricky, so done with clang-rename.

Change-Id: Ie959b86e9e82b11b211761b0c73e439e51044de7
Reviewed-on: https://pdfium-review.googlesource.com/7410
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/core/fpdfapi/parser/cpdf_syntax_parser.cpp b/core/fpdfapi/parser/cpdf_syntax_parser.cpp
index 9dccbd9..ce5a835 100644
--- a/core/fpdfapi/parser/cpdf_syntax_parser.cpp
+++ b/core/fpdfapi/parser/cpdf_syntax_parser.cpp
@@ -387,10 +387,10 @@
     if (bIsNumber) {
       CFX_ByteString nextword2 = GetNextWord(nullptr);
       if (nextword2 == "R") {
-        uint32_t objnum = FXSYS_atoui(word.c_str());
-        if (objnum == CPDF_Object::kInvalidObjNum)
+        uint32_t refnum = FXSYS_atoui(word.c_str());
+        if (refnum == CPDF_Object::kInvalidObjNum)
           return nullptr;
-        return pdfium::MakeUnique<CPDF_Reference>(pObjList, objnum);
+        return pdfium::MakeUnique<CPDF_Reference>(pObjList, refnum);
       }
     }
     m_Pos = SavedPos;
@@ -508,10 +508,10 @@
     if (bIsNumber) {
       CFX_ByteString nextword2 = GetNextWord(nullptr);
       if (nextword2 == "R") {
-        uint32_t objnum = FXSYS_atoui(word.c_str());
-        if (objnum == CPDF_Object::kInvalidObjNum)
+        uint32_t refnum = FXSYS_atoui(word.c_str());
+        if (refnum == CPDF_Object::kInvalidObjNum)
           return nullptr;
-        return pdfium::MakeUnique<CPDF_Reference>(pObjList, objnum);
+        return pdfium::MakeUnique<CPDF_Reference>(pObjList, refnum);
       }
     }
     m_Pos = SavedPos;
diff --git a/core/fxcrt/fx_system_unittest.cpp b/core/fxcrt/fx_system_unittest.cpp
index 7747086..da616b4 100644
--- a/core/fxcrt/fx_system_unittest.cpp
+++ b/core/fxcrt/fx_system_unittest.cpp
@@ -184,8 +184,9 @@
 
   for (int year = -2500; year <= 2500; ++year) {
     year_time.tm_year = year;
-    wchar_t buf[100] = {};
-    FXSYS_wcsftime(buf, FX_ArraySize(buf), L"%Y-%m-%dT%H:%M:%S", &year_time);
+    wchar_t year_buf[100] = {};
+    FXSYS_wcsftime(year_buf, FX_ArraySize(year_buf), L"%Y-%m-%dT%H:%M:%S",
+                   &year_time);
   }
 
   // Ensure wcsftime handles bad years, etc. without crashing.