Added new ReadFileToString API with a max_size argument

base/file_util_unittest.cc

Index: base/file_util_unittest.cc
diff --git a/base/file_util_unittest.cc b/base/file_util_unittest.cc
index d3c246e42928675bcf08a9e0b242294ba58a30e6..22c4f6d9fed8e434fadfb99916b60ad1fe075001 100644
--- a/base/file_util_unittest.cc
+++ b/base/file_util_unittest.cc
@@ -1924,6 +1924,48 @@ TEST_F(FileUtilTest, AppendToFile) {
   EXPECT_EQ(L"hellohello", read_content);
 }
 
+TEST_F(FileUtilTest, ReadFileToString) {
+  const char kTestData[] = "0123";
+  std::string data;
+
+  FilePath file_path =
+      temp_dir_.path().Append(FILE_PATH_LITERAL("ReadFileToStringTest"));
+
+  ASSERT_EQ(4, file_util::WriteFile(file_path, kTestData, 4));
+
+  EXPECT_TRUE(ReadFileToString(file_path, &data));
+  EXPECT_EQ(kTestData, data);
+
+  data.clear();
+  EXPECT_FALSE(ReadFileToString(file_path, &data, 0));
+  EXPECT_EQ(data.length(), (size_t)0);

[bartfab (slow), 2014/02/11 12:51:12]

Nit: Use C++-style casts, not C-style casts. In this case, you can avoid all
casts by using 0u instead of 0.

[kaliamoorthi, 2014/02/11 16:29:16]

Done.

+
+  data.clear();
+  EXPECT_FALSE(ReadFileToString(file_path, &data, 2));
+  EXPECT_EQ(data.length(), (size_t)0);
+
+  data.clear();
+  EXPECT_FALSE(ReadFileToString(file_path, &data, 3));
+  EXPECT_EQ(data.length(), (size_t)0);
+
+  data.clear();
+  EXPECT_TRUE(ReadFileToString(file_path, &data, 4));
+  EXPECT_EQ("0123", data);
+
+  data.clear();
+  EXPECT_TRUE(ReadFileToString(file_path, &data, 6));
+  EXPECT_EQ("0123", data);
+
+  EXPECT_TRUE(ReadFileToString(file_path, NULL, 6));
+
+  EXPECT_TRUE(ReadFileToString(file_path, NULL));
+
+  // Make sure we can & do delete the created file to prevent leaks on the bots.

[bartfab (slow), 2014/02/11 12:51:12]

Nit 1: Avoid abbreviations, s/&/and/.
Nit 2: The comment is unnecessary and misleading. Yes, one purpose of deleting
the file is to prevent leaks on bots. But you also use the nonexistence of the
file for further testing.

[kaliamoorthi, 2014/02/11 16:29:16]

Done.

+  EXPECT_TRUE(base::DeleteFile(file_path, false));

[bartfab (slow), 2014/02/11 12:51:12]

Nit: For readability, add a blank like after this one.

[kaliamoorthi, 2014/02/11 16:29:16]

Done.

+  EXPECT_FALSE(ReadFileToString(file_path, &data));
+  EXPECT_FALSE(ReadFileToString(file_path, &data, 6));
+}
+
 TEST_F(FileUtilTest, TouchFile) {
   FilePath data_dir =
       temp_dir_.path().Append(FILE_PATH_LITERAL("FilePathTest"));