Implement PrintPageAsJPEG feature for Print Preview

Implement PrintPageAsJPEG feature for Print Preview.

In order to show the tab contents to the print tab, the renderer should print the page as a JPEG image so it could be rendered in the DOMUI. A unit test case has been created to make sure the image contains something from deciding whether its not 100% white.

MockPrinter has been altered to remove the const parameter, since its useful to retrieve the DefaultSettings not via IPC.

BUG=173
(http://crbug.com/173)
TEST=created a unit test and ran it.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=25445

[Mohamed Mansour, 2009-09-04 02:49:26]

One problem though, for 
src/chrome/renderer/mock_render_thread.h

I cannot use printer(), I made another one called printers(). Could someone
assist me in how I could reuse "printer()" I am having too much const weirdness.

[M-A Ruel, 2009-09-04 03:59:07]

lgtm with small nits.

http://codereview.chromium.org/196021/diff/2001/2002
File src/chrome/renderer/mock_render_thread.h (right):

http://codereview.chromium.org/196021/diff/2001/2002#newcode73
Line 73: const MockPrinter* printer() const { return printer_.get(); }
Remove this function then. When const gets in the way we just remove it.

http://codereview.chromium.org/196021/diff/2001/2002#newcode75
Line 75: private:
keep an empty line before this one.

http://codereview.chromium.org/196021/diff/2001/2006
File src/chrome/renderer/print_web_view_helper.h (right):

http://codereview.chromium.org/196021/diff/2001/2006#newcode78
Line 78: // Prints the page as a bitmap.
as a jpeg? Please clarify the comment.

[Mohamed Mansour, 2009-09-04 05:10:18]

Applied maruel's comments.

http://codereview.chromium.org/196021/diff/2001/2002
File src/chrome/renderer/mock_render_thread.h (right):

http://codereview.chromium.org/196021/diff/2001/2002#newcode73
Line 73: const MockPrinter* printer() const { return printer_.get(); }
On 2009/09/04 03:59:07, Marc-Antoine Ruel wrote:
> Remove this function then. When const gets in the way we just remove it.

Done.

http://codereview.chromium.org/196021/diff/2001/2002#newcode75
Line 75: private:
On 2009/09/04 03:59:07, Marc-Antoine Ruel wrote:
> keep an empty line before this one.

Done.

http://codereview.chromium.org/196021/diff/2001/2006
File src/chrome/renderer/print_web_view_helper.h (right):

http://codereview.chromium.org/196021/diff/2001/2006#newcode78
Line 78: // Prints the page as a bitmap.
On 2009/09/04 03:59:07, Marc-Antoine Ruel wrote:
> as a jpeg? Please clarify the comment.

Done.

[Hironori Bono, 2009-09-04 06:16:33]

LGTM
Thank you for your change.

Regards,

Hironori Bono