Fullscreen tab capture: Prefer standard resolutions

Fullscreen tab capture: Prefer standard resolutions

While testing the use of auto-throttling capture with fullscreen
content, it became clear that using the user's screen size as a maximum
resulted in poor-quality scaling situations.  For example, logic which
fits the 16:9 content into a screen with 768 vertical lines resulted in
an odd 1365x768 capture resolution that looked a bit blurry.

This change adds logic to detect when a common video aspect ratio is
being used, such as 16:9, and rounds down to a standard resolution with
even dimensions.  For example, 1365x768 is rounded down to 1280x720.

BUG=156767
Committed: https://crrev.com/e29bedb115b69f5c647ae7bcdcd72cc2435b2060
Cr-Commit-Position: refs/heads/master@{#341220}

[miu, 2015-07-29 23:46:47]

Patchset #1 (id:1) has been deleted

[miu, 2015-07-29 23:47:49]

miu@chromium.org changed reviewers:
+ marshallk@google.com

[miu, 2015-07-29 23:47:50]

marshallk: PTAL.

[Kevin M, 2015-07-30 00:23:05]

kmarshall@chromium.org changed reviewers:
+ kmarshall@chromium.org

[Kevin M, 2015-07-30 00:23:06]

https://codereview.chromium.org/1256183003/diff/20001/content/browser/media/c...
File content/browser/media/capture/web_contents_video_capture_device.cc (right):

https://codereview.chromium.org/1256183003/diff/20001/content/browser/media/c...
content/browser/media/capture/web_contents_video_capture_device.cc:651: const
auto HasIntendedAspectRatio = [](const gfx::Size& size, int x, int y) {
Can you factor this out into a standalone fn that takes gfx::Size and write some
unit tests for it?

https://codereview.chromium.org/1256183003/diff/20001/content/browser/media/c...
content/browser/media/capture/web_contents_video_capture_device.cc:658: const
int adjusted_height =
Can you add some comments or pick a more descriptive name for x & y to
communicate the requirements for even multiples?

[miu, 2015-07-30 20:22:54]

PTAL.  (Also, please make sure you're using your @chromium.org account when you
ell-gee-tee-em.)

https://codereview.chromium.org/1256183003/diff/20001/content/browser/media/c...
File content/browser/media/capture/web_contents_video_capture_device.cc (right):

https://codereview.chromium.org/1256183003/diff/20001/content/browser/media/c...
content/browser/media/capture/web_contents_video_capture_device.cc:651: const
auto HasIntendedAspectRatio = [](const gfx::Size& size, int x, int y) {
On 2015/07/30 00:23:06, Kevin M wrote:
> Can you factor this out into a standalone fn that takes gfx::Size and write
some
> unit tests for it?

Done.  Didn't factor anything out, but did write unit tests.

https://codereview.chromium.org/1256183003/diff/20001/content/browser/media/c...
content/browser/media/capture/web_contents_video_capture_device.cc:658: const
int adjusted_height =
On 2015/07/30 00:23:06, Kevin M wrote:
> Can you add some comments or pick a more descriptive name for x & y to
> communicate the requirements for even multiples?

Done.

[Kevin M, 2015-07-30 20:33:19]

lgtm

[miu, 2015-07-30 21:25:56]

The CQ bit was checked by miu@chromium.org

[commit-bot: I haz the power, 2015-07-30 21:26:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1256183003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1256183003/40001

[commit-bot: I haz the power, 2015-07-30 23:13:39]

Committed patchset #2 (id:40001)

[commit-bot: I haz the power, 2015-07-30 23:14:15]

Patchset 2 (id:??) landed as
https://crrev.com/e29bedb115b69f5c647ae7bcdcd72cc2435b2060
Cr-Commit-Position: refs/heads/master@{#341220}