Switch HTMLCanvasElement over to new-style ExceptionState.

Switch HTMLCanvasElement over to new-style ExceptionState.

Set up the calling context on toDataURL()'s incoming ExceptionState
instead, for tidier generation of a possible SecurityError exception.

To support throwing context-sensitive SecurityErrors, extend
throwSecurityError() to also embellish its incoming messages.

R=
BUG=270033
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=162887

[sof, 2013-11-29 06:41:08]

At your leisure, please take a look.

[Mike West, 2013-11-29 08:26:44]

LGTM, thanks for working on this! :)

-mike

https://codereview.chromium.org/96203003/diff/1/Source/core/html/HTMLCanvasEl...
File Source/core/html/HTMLCanvasElement.cpp (right):

https://codereview.chromium.org/96203003/diff/1/Source/core/html/HTMLCanvasEl...
Source/core/html/HTMLCanvasElement.cpp:376:
exceptionState.throwSecurityError("tainted canvases may not be exported.");
Nit: If you're changing this anyway, can you capitalize "Tainted"?

[sof, 2013-11-29 08:58:03]

https://codereview.chromium.org/96203003/diff/1/Source/core/html/HTMLCanvasEl...
File Source/core/html/HTMLCanvasElement.cpp (right):

https://codereview.chromium.org/96203003/diff/1/Source/core/html/HTMLCanvasEl...
Source/core/html/HTMLCanvasElement.cpp:376:
exceptionState.throwSecurityError("tainted canvases may not be exported.");
On 2013/11/29 08:26:45, Mike West wrote:
> Nit: If you're changing this anyway, can you capitalize "Tainted"?

Done, and same for the other taint-related error messages.

(Will assume ok and proceed to commit.)

[commit-bot: I haz the power, 2013-11-29 08:58:34]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/sigbjornf@opera.com/96203003/20001

[commit-bot: I haz the power, 2013-11-29 10:08:25]

Change committed as 162887