Fix more sign comparison errors.

fpdfsdk/src/fpdftext_embeddertest.cpp

 // Copyright 2015 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "../../public/fpdf_text.h"
 #include "../../public/fpdfview.h"
 #include "../../testing/embedder_test.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace {
@@ skipping 22 matching lines @@
   EXPECT_NE(nullptr, page);
 
   FPDF_TEXTPAGE textpage = FPDFText_LoadPage(page);
   EXPECT_NE(nullptr, textpage);
 
   static const char expected[] = "Hello, world!\r\nGoodbye, world!";
   unsigned short fixed_buffer[128];
   memset(fixed_buffer, 0xbd, sizeof(fixed_buffer));
 
   // Check includes the terminating NUL that is provided.
-  EXPECT_EQ(sizeof(expected), FPDFText_GetText(textpage, 0, 128, fixed_buffer));
+  int num_chars = FPDFText_GetText(textpage, 0, 128, fixed_buffer);
+  ASSERT_GE(num_chars, 0);
+  EXPECT_EQ(sizeof(expected), static_cast<size_t>(num_chars));
   EXPECT_TRUE(check_unsigned_shorts(expected, fixed_buffer, sizeof(expected)));
 
   // Count does not include the terminating NUL in the string literal.
   EXPECT_EQ(sizeof(expected) - 1, FPDFText_CountChars(textpage));
   for (size_t i = 0; i < sizeof(expected) - 1; ++i) {
-    EXPECT_EQ(expected[i], FPDFText_GetUnicode(textpage, i)) << " at " << i;
+    EXPECT_EQ(static_cast<unsigned int>(expected[i]),
+              FPDFText_GetUnicode(textpage, i))
+        << " at " << i;
   }
 
   EXPECT_EQ(12.0, FPDFText_GetFontSize(textpage, 0));
   EXPECT_EQ(16.0, FPDFText_GetFontSize(textpage, 15));
 
   double left = 0.0;
   double right = 0.0;
   double bottom = 0.0;
   double top = 0.0;
   FPDFText_GetCharBox(textpage, 4, &left, &right, &bottom, &top);
@@ skipping 291 matching lines @@
   FPDFLink_GetRect(pagelink, -1, 0, &left, &top, &right, &bottom);
   EXPECT_EQ(-2.0, left);
   EXPECT_EQ(-2.0, right);
   EXPECT_EQ(-2.0, bottom);
   EXPECT_EQ(-2.0, top);
 
   FPDFLink_CloseWebLinks(pagelink);
   FPDFText_ClosePage(textpage);
   UnloadPage(page);
 }