Fix some sign comparison warnings.

fpdfsdk/src/fpdfdoc_embeddertest.cpp

Index: fpdfsdk/src/fpdfdoc_embeddertest.cpp
diff --git a/fpdfsdk/src/fpdfdoc_embeddertest.cpp b/fpdfsdk/src/fpdfdoc_embeddertest.cpp
index 9c9fac8d150f2dd83da6a5cbfe1355ece5f97bbb..b263fafe16905a3c448e0b9e9b0f4861a2d67059 100644
--- a/fpdfsdk/src/fpdfdoc_embeddertest.cpp
+++ b/fpdfsdk/src/fpdfdoc_embeddertest.cpp
@@ -13,25 +13,25 @@ TEST_F(FPDFDocEmbeddertest, DestGetPageIndex) {
   EXPECT_TRUE(OpenDocument("testing/resources/named_dests.pdf"));
 
   // NULL FPDF_DEST case.
-  EXPECT_EQ(0, FPDFDest_GetPageIndex(document(), nullptr));
+  EXPECT_EQ(0U, FPDFDest_GetPageIndex(document(), nullptr));
 
   // Page number directly in item from Dests NameTree.
   FPDF_DEST dest = FPDF_GetNamedDestByName(document(), "First");
   EXPECT_NE(nullptr, dest);
-  EXPECT_EQ(1, FPDFDest_GetPageIndex(document(), dest));
+  EXPECT_EQ(1U, FPDFDest_GetPageIndex(document(), dest));
 
   // Page number via object reference in item from Dests NameTree.
   dest = FPDF_GetNamedDestByName(document(), "Next");
   EXPECT_NE(nullptr, dest);
-  EXPECT_EQ(1, FPDFDest_GetPageIndex(document(), dest));
+  EXPECT_EQ(1U, FPDFDest_GetPageIndex(document(), dest));
 
   // Page number directly in item from Dests dictionary.
   dest = FPDF_GetNamedDestByName(document(), "FirstAlternate");
   EXPECT_NE(nullptr, dest);
-  EXPECT_EQ(11, FPDFDest_GetPageIndex(document(), dest));
+  EXPECT_EQ(11U, FPDFDest_GetPageIndex(document(), dest));
 
   // Invalid object reference in item from Dests NameTree.
   dest = FPDF_GetNamedDestByName(document(), "LastAlternate");
   EXPECT_NE(nullptr, dest);
-  EXPECT_EQ(0, FPDFDest_GetPageIndex(document(), dest));
+  EXPECT_EQ(0U, FPDFDest_GetPageIndex(document(), dest));
 }