FileVideoCaptureDevice: better error mgmt if !File.IsValid()

FileVideoCaptureDevice: better error mgmt if !File.IsValid()

Apparently on Windows platforms there's a small but nonzero crash rate
due to CHECK(file.IsValid()) in FileVideoCaptureDevice::OpenFileForRead().

Do not CHECK() there, instead let the callers deal with the problem,
so that there is no crash either (capture won't work of course).

BUG=466408
Committed: https://crrev.com/72aaef796a92aac5aac80f315845215f0deebc64
Cr-Commit-Position: refs/heads/master@{#321139}

[mcasas, 2015-03-17 18:42:24]

mcasas@chromium.org changed reviewers:
+ phoglund@chromium.org

[mcasas, 2015-03-17 18:42:25]

phoglund@ PTAL

[phoglund_chromium, 2015-03-18 07:57:50]

Yeah, I guess the best we can do is log the error and exit gracefully (except
possibly rendering FAILED TO OPEN <file path> in the video flow :)

lgtm

[mcasas, 2015-03-18 14:50:35]

The CQ bit was checked by mcasas@chromium.org

[commit-bot: I haz the power, 2015-03-18 14:50:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1017633004/1

[commit-bot: I haz the power, 2015-03-18 15:43:26]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-18 15:44:26]

Patchset 1 (id:??) landed as
https://crrev.com/72aaef796a92aac5aac80f315845215f0deebc64
Cr-Commit-Position: refs/heads/master@{#321139}

[mcasas, 2015-03-18 16:37:36]

On 2015/03/18 07:57:50, phoglund wrote:
> Yeah, I guess the best we can do is log the error and exit gracefully (except
> possibly rendering FAILED TO OPEN <file path> in the video flow :)

Hey I like that suggestion :D

> 
> lgtm