Fix SafeAdd and SafeMultiply

gpu/command_buffer/common/gles2_cmd_utils_unittest.cc

Index: gpu/command_buffer/common/gles2_cmd_utils_unittest.cc
diff --git a/gpu/command_buffer/common/gles2_cmd_utils_unittest.cc b/gpu/command_buffer/common/gles2_cmd_utils_unittest.cc
index 0bf11f07ce42c59909e13afe305e2cd211a9f644..0e157dbfcac32ff6d3ad73060ade6c489c869d66 100644
--- a/gpu/command_buffer/common/gles2_cmd_utils_unittest.cc
+++ b/gpu/command_buffer/common/gles2_cmd_utils_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 
+#include <limits>
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
 
@@ -17,6 +18,58 @@ class GLES2UtilTest : public testing:: Test {
   GLES2Util util_;
 };
 
+TEST_F(GLES2UtilTest, SafeMultiplyUint32) {
+  uint32 result = 0;
+  EXPECT_TRUE(SafeMultiplyUint32(2u, 3u, &result));
+  EXPECT_EQ(6u, result);
+  EXPECT_FALSE(SafeMultiplyUint32(0x80000000u, 2u, &result));
+  EXPECT_EQ(0u, result);
+  EXPECT_TRUE(SafeMultiplyUint32(0x2u, 0x7FFFFFFFu, &result));
+  EXPECT_EQ(0xFFFFFFFEu, result);
+  EXPECT_FALSE(SafeMultiplyUint32(2u, 0x80000000u, &result));
+  EXPECT_EQ(0u, result);
+}
+
+TEST_F(GLES2UtilTest, SafeAddUint32) {
+  uint32 result = 0;
+  EXPECT_TRUE(SafeAddUint32(2u, 3u, &result));
+  EXPECT_EQ(5u, result);
+  EXPECT_FALSE(SafeAddUint32(0x80000000u, 0x80000000u, &result));
+  EXPECT_EQ(0u, result);
+  EXPECT_TRUE(SafeAddUint32(0xFFFFFFFEu, 0x1u, &result));
+  EXPECT_EQ(0xFFFFFFFFu, result);
+  EXPECT_FALSE(SafeAddUint32(0xFFFFFFFEu, 0x2u, &result));
+  EXPECT_EQ(0u, result);
+  EXPECT_TRUE(SafeAddUint32(0x1u, 0xFFFFFFFEu, &result));
+  EXPECT_EQ(0xFFFFFFFFu, result);
+  EXPECT_FALSE(SafeAddUint32(0x2u, 0xFFFFFFFEu, &result));
+  EXPECT_EQ(0u, result);
+}
+
+TEST_F(GLES2UtilTest, SafeAddInt32) {
+  int32 result = 0;
+  const int32 kMax = std::numeric_limits<int32>::max();
+  const int32 kMin = std::numeric_limits<int32>::min();
+  EXPECT_TRUE(SafeAddInt32(2, 3, &result));
+  EXPECT_EQ(5, result);
+  EXPECT_FALSE(SafeAddInt32(kMax, 1, &result));
+  EXPECT_EQ(0, result);
+  EXPECT_TRUE(SafeAddInt32(kMin + 1, -1, &result));
+  EXPECT_EQ(kMin, result);
+  EXPECT_FALSE(SafeAddInt32(kMin, -1, &result));
+  EXPECT_EQ(0, result);
+  EXPECT_TRUE(SafeAddInt32(kMax - 1, 1, &result));
+  EXPECT_EQ(kMax, result);
+  EXPECT_FALSE(SafeAddInt32(1, kMax, &result));
+  EXPECT_EQ(0, result);
+  EXPECT_TRUE(SafeAddInt32(-1, kMin + 1, &result));
+  EXPECT_EQ(kMin, result);
+  EXPECT_FALSE(SafeAddInt32(-1, kMin, &result));
+  EXPECT_EQ(0, result);
+  EXPECT_TRUE(SafeAddInt32(1, kMax - 1, &result));
+  EXPECT_EQ(kMax, result);
+}
+
 TEST_F(GLES2UtilTest, GLGetNumValuesReturned) {
   EXPECT_EQ(0, util_.GLGetNumValuesReturned(GL_COMPRESSED_TEXTURE_FORMATS));
   EXPECT_EQ(0, util_.GLGetNumValuesReturned(GL_SHADER_BINARY_FORMATS));