Question: Who is the director of the film that featured the song "What If" by Colbie Caillat on its soundtrack?

Context paragraphs:
Colbie Caillat discography: The discography of Colbie Caillat, an American musician and singer-songwriter, contains six studio albums, seven extended plays, one compilation album, twenty-two singles (including six as a featured artist), twenty-two music videos and other album appearances and songwriting credits.  Caillat rose to fame through social networking website Myspace.  At that time, she was the number-one unsigned artist of her genre.  After signing with Universal Republic, she released debut album in July 2007, "Coco" has sold 2,060,000 copies in the United States and is certified 2× Platinum.  In August 2009, she released "Breakthrough", her second album which became her first album to debut at number one on "Billboard" 200.  It has been certified Gold by RIAA.  In July 2011, she released her third studio album, "All of You".  In October 2012 she released her first Christmas album, "Christmas in the Sand".  Caillat sold 6 million albums and 10 million singles worldwide.

Fallin' for You (Colbie Caillat song): "Fallin' for You" is a song by American singer-songwriter Colbie Caillat.  It was written by Caillat along with Rick Nowels, and produced by Nowels, John Shanks, and Caillat's father Ken Caillat, for her second studio album "Breakthrough" (2009).  The song was released on June 26, 2009 as the lead single from the album, through Universal Republic.  Musically, the song is a pop ballad, and the lyrics, according to Caillat, speak of people falling for a guy that they are friends with.

Coco (album): Coco is the debut studio album by American singer-songwriter Colbie Caillat.  The album was released on July 17, 2007 in the United States, debuting at number six on the US "Billboard" 200, selling 51,000 copies in its first week.  It also became Caillat's best-selling album to date, selling 2,100,000 copies in the United States and over 3,000,000 copies around the world.  Caillat supported the album with the "Coco World Tour", as well as four singles.  The lead single "Bubbly" was a huge international hit, while the following two singles "Realize" and "The Little Things" were minor hits.  The final single, titled "Somethin' Special" was released on 29 July 2008 to support the 2008 Summer Olympics in Beijing, China.  It was later mixed and titled "Somethin' Special (Beijing Olympic Mix)".

Christmas in the Sand: Christmas in the Sand is a Christmas album and the fourth studio album by American singer-songwriter Colbie Caillat.  The album was released on October 23, 2012 in the United States through Universal Republic Records.  The album includes eight cover versions of popular Holidays songs and four original songs written by Caillat along with other songwriters.  Produced by Ken Caillat, the album features collaborations with Brad Paisley, Gavin DeGraw, Justin Young and Jason Reeves.  The first single "Christmas in the Sand" was released through Soundcloud on October 15, 2012 and "Merry Christmas Baby" was released on October 16, 2012, which features country music artist Brad Paisley.  The album also has a deluxe edition, that was released through Target and that includes three bonus tracks.  This is the last album that Caillat released on Universal Republic Records; her future material would be released through Republic Records.

Christmas in the Sand (song): "Christmas in the Sand" is a Christmas song recorded by American singer-songwriter Colbie Caillat.  It was written by Caillat, Jason Reeves and Kara DioGuardi and produced by Colbie's father, Ken Caillat.  The song was released as the first single from her first Christmas album "Christmas in the Sand".  The song was released to SoundCloud on October 15, 2012 through Universal Republic.

Mikal Blue: Mikal Blue (born 3 March 1966) is an English music producer, songwriter, engineer and mixer best known for his work with Colbie Caillat, Jason Reeves, Jason Mraz, Five For Fighting and OneRepublic.  Originally from County Durham, England, Mikal Blue is currently based in Los Angeles and works from his studio "Revolver Recordings" in Thousand Oaks, California.  In addition to his work as a producer, songwriter, engineer, mixer and instrumentalist, Blue has worked in developing acts such as Augustana, OneRepublic, Colbie Caillat, Angel Taylor, Chandler Juliet and Kevin Hammond.

Try (Colbie Caillat song): "Try" is a song recorded by American singer-songwriter Colbie Caillat from her fifth studio album, "Gypsy Heart".  It was released as the lead single on June 9, 2014 via Republic Records.  The song was written by Caillat, Babyface and Jason Reeves and was produced by Babyface.  Lyrically, the midtempo ballad is about not trying to be someone else in order to make others happy and it was written after a session where Caillat was feeling pressure to be someone she was not, both musically and image-wise.  It received acclaim from music critics, who noted it was a simple, but beautiful empowering ballad.

Bubbly: "Bubbly" is the debut single by American singer Colbie Caillat from her debut album, "Coco" (2007).  Written by Caillat and Jason Reeves and produced by Mikal Blue, the song was released as the album's lead single on May 15, 2007.  It remains Caillat's biggest hit in the US to date, and her only single to reach the top ten of the "Billboard" Hot 100.

What If (Colbie Caillat song): "What If" is a song recorded by American recording artist Colbie Caillat.  It was written by Caillat, Rick Nowels and Jason Reeves, and produced by John Shanks.  The song was released as a promotional single from the soundtrack of the film Letters to Juliet and later was included on her third studio album "All of You".

Letters to Juliet: Letters to Juliet is a 2010 American romantic drama film starring Amanda Seyfried, Christopher Egan, Vanessa Redgrave, Gael García Bernal and Franco Nero.  This was the final film of director Gary Winick.  The film was released theatrically in North America and other countries on May 14, 2010.  The idea for the film was inspired by the 2006 non-fiction book "Letters to Juliet", by Lise Friedman and Ceil Friedman, which chronicles the phenomenon of letter-writing to Shakespeare's most famous romantic heroine.

Supporting paragraphs: What If (Colbie Caillat song) Letters to Juliet
Answer: Gary Winick