Add bitmap.mojom definition and typeconverters

Add bitmap.mojom definition and typeconverters

This CL is splitted out from the CL
https://codereview.chromium.org/1028543002/
created by amistry <amistry@chromium.org>;.

This CL purely provides skia.Bitmap(bitmap.mojom) definition
and TypeConverters between SkBitmap and skia::BitmapPtr.

TBR=amistry@chromium.org,rockot@chromium.org,edisonn@google.com
BUG=

[haltonhuo, 2015-04-17 06:00:35]

halton.huo@intel.com changed reviewers:
+ djsollen@chromium.org

[haltonhuo, 2015-04-17 06:00:35]

This CL is offered by Leon Han<leon.han@intel.com> who has "git cl upload"
issue.

[leonhsl(Using Gerrit), 2015-04-17 06:10:58]

leon.han@intel.com changed reviewers:
+ leon.han@intel.com

[leonhsl(Using Gerrit), 2015-04-17 06:10:58]

Split out from https://codereview.chromium.org/1028543002/ to provide purely
bitmap.mojom definition and TypeConverters.
PTAL, Thanks~

[Ken Rockot(use gerrit already), 2015-04-17 17:37:59]

lgtm, but you will also want a skia owner to review

[leonhsl(Using Gerrit), 2015-04-20 03:00:23]

leon.han@intel.com changed reviewers:
+ vandebo@chromium.org
- amistry@chromium.org, djsollen@chromium.org, edisonn@google.com,
rockot@chromium.org

[leonhsl(Using Gerrit), 2015-04-20 03:00:24]

+vandebo@chromium.org
Hi, could you help to review this CL as OWNER? Thanks a lot~

[leonhsl(Using Gerrit), 2015-04-20 03:03:28]

leon.han@intel.com changed reviewers:
+ amistry@chromium.org

[vandebo (ex-Chrome), 2015-04-20 15:10:24]

vandebo@chromium.org changed reviewers:
+ reed@google.com

[vandebo (ex-Chrome), 2015-04-20 15:10:24]

Better skia/ owners

[reed1, 2015-04-20 16:07:43]

would like to understand the larger CL first (i.e. the use-cases for these
conversions)

[Anand Mistry (off Chromium), 2015-04-29 23:00:12]

On 2015/04/20 16:07:43, reed1 wrote:
> would like to understand the larger CL first (i.e. the use-cases for these
> conversions)

The motivation for this change is to be able to pass SkBitmaps over Mojo IPC.
"type converters" are the canonical Mojo way of converting between C++ and Mojo
structures. This is essentially an analog of the Chrome IPC serialisation code
in
https://code.google.com/p/chromium/codesearch#chromium/src/ui/gfx/ipc/gfx_par....

As for use cases, there are two in progress.
https://codereview.chromium.org/1085783002/ which converts the "image
downloading" content IPCs to Mojo, and
https://codereview.chromium.org/1028543002/ which converts the utility process
image decoder to Mojo. Basically, anywhere we need to pass an SkBitmap over
Mojo, we need this, of something like it.

[leonhsl(Using Gerrit), 2015-05-07 05:36:57]

Hi, 
@Reed1, Would you check this CL again based on Amistry's explanation? Thanks a
lot.

[haltonhuo, 2015-06-17 08:14:58]

Closed as https://codereview.chromium.org/1150083005 is landed.