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..483ef6600ec1379f81ab83178dabaf960c89566a 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -133,10 +133,24 @@ 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.

[bartfab (slow), 2014/02/18 14:56:51]

Nit: The sentence now says that the function is "useful for" X which is "useful
for" Y. Not exactly the best wording possible :).

+// The function replaces rather than append to |contents|, further |contents|

[bartfab (slow), 2014/02/18 14:56:51]

Nit 1: s/append/appending/
Nit 2: Document the behavior on error in a separate sentence.
Nit 3: "could be cleared" leaves the actual behavior undefined. Better state
when the contents is cleared and when it is not.

+// could be cleared on error.
 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

[bartfab (slow), 2014/02/18 14:56:51]

Nit: The sentence now says that the function is "useful for" X which is "useful
for" Y. Not exactly the best wording possible :).

+// side effect of priming the disk cache, which is useful for unit tests.
+// The function replaces rather than append to |contents|, further |contents|

[bartfab (slow), 2014/02/18 14:56:51]

Nit 1: s/append/appending/
Nit 2: Document the behavior on error in a separate sentence.
Nit 3: "could be cleared" leaves the actual behavior undefined. Better state
when the contents is cleared and when it is not.

+// could be cleared on error.
+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