Added new ReadFileToString API with a max_size argument

base/file_util.h

Index: base/file_util.h
diff --git a/base/file_util.h b/base/file_util.h
index f8418318a6a7ecd92255e6d708624b7f1ae6bcf7..320862d223354f36d220bd0dcb70b02ced21fc73 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -133,10 +133,20 @@ BASE_EXPORT bool TextContentsEqual(const FilePath& filename1,
 // Read the file at |path| into |contents|, returning true on success.
 // This function fails if the |path| contains path traversal components ('..').
 // |contents| may be NULL, in which case this function is useful for its
-// side effect of priming the disk cache.
-// Useful for unit tests.
+// side effect of priming the disk cache, which is useful for unit tests.
 BASE_EXPORT bool ReadFileToString(const FilePath& path, std::string* contents);
 
+// Read the file at |path| into |contents|, returning true on success.
+// This function has an additional check on the maximum size of the file.
+// When the file size is greater than |max_size|, the function reads |max_size|
+// bytes into |contents| and returns false.
+// This function fails if the |path| contains path traversal components ('..').
+// |contents| may be NULL, in which case this function is useful for its
+// side effect of priming the disk cache, which is useful for unit tests.
+BASE_EXPORT bool ReadFileToString(const FilePath& path,
+                                  std::string* contents,
+                                  size_t max_size);
+
 #if defined(OS_POSIX)
 
 // Read exactly |bytes| bytes from file descriptor |fd|, storing the result