Reland rewrite clipboard write IPC handling to be easier to understand.

Reland rewrite clipboard write IPC handling to be easier to understand.

The original implementation sent clipboard data to be written over IPC
as a map of clipboard formats to 'parameters' for that format. The
parameters were just vectors of byte vectors. Needless to say, this
logic was complicated, fragile, and prone to bugs. In the browser
process, this resulted in the IPC validation logic being scattered
between ClipboardMessageFilter and Clipboard::DispatchObject.

The rewrite adds an IPC message for each flavor of data that the
renderer is allowed to write to the clipboard. On the browser side,
the logic is simply delegated to ScopedClipboardWriter. Since the
clipboard object map is no longer under the control of an untrusted
process, this allows the removal of a lot of validation logic.
Unfortunately, bitmap handling is still a bit complicated because it's
sent over shared memory, but all the validation logic has been moved
into ClipboardMessageFilter.

BUG=319285
TBR=avi@chromium.org,jamesr@chromium.org,wfh@chromium.org

Committed: https://crrev.com/112adc89f9665f2fd37c1882e1619d183dbbcea0
Cr-Commit-Position: refs/heads/master@{#304988}

[dcheng, 2014-11-20 00:06:10]

dcheng@chromium.org changed reviewers:
+ sky@chromium.org

[dcheng, 2014-11-20 00:06:11]

PS1 to PS2 has the diffs to fix the crash. The problem is some callsites in
Chrome would call ScopedClipboardWriter::WriteFoo() with empty strings. This
crashed inside DispatchObject when we tried to get a pointer to the data in the
vector.

I opted for the lazy fix: at some point in the future, I plan on changing how
ScopedClipboardWriter/Clipboard pass data around. Vectors of vectors of bytes
are very flexible, but have problems like this =/

[sky, 2014-11-20 05:04:22]

LGTM

[dcheng, 2014-11-20 05:09:45]

The CQ bit was checked by dcheng@chromium.org

[dcheng, 2014-11-20 05:09:50]

The CQ bit was unchecked by dcheng@chromium.org

[dcheng, 2014-11-20 05:11:16]

dcheng@chromium.org changed reviewers:
+ avi@chromium.org, jamesr@chromium.org, wfh@chromium.org

[dcheng, 2014-11-20 05:12:00]

TBRing previous reviewers as bits outside ui/ have not changed.

[dcheng, 2014-11-20 05:12:06]

The CQ bit was checked by dcheng@chromium.org

[commit-bot: I haz the power, 2014-11-20 05:13:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/740763003/40001

[Avi (use Gerrit), 2014-11-20 05:17:16]

On 2014/11/20 05:12:00, dcheng wrote:
> TBRing previous reviewers as bits outside ui/ have not changed.

SLGTM

[commit-bot: I haz the power, 2014-11-20 07:16:59]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2014-11-20 07:17:37]

Patchset 3 (id:??) landed as
https://crrev.com/112adc89f9665f2fd37c1882e1619d183dbbcea0
Cr-Commit-Position: refs/heads/master@{#304988}